MQTT - RS485 Bricklet

This is the description of the MQTT API bindings for the RS485 Bricklet. General information and technical specifications for the RS485 Bricklet are summarized in its hardware description.

An installation guide for the MQTT API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Loopback

Download (example-loopback.txt)

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# For this example connect the RX+/- pins to TX+/- pins on the same Bricklet
# and configure the DIP switch on the Bricklet to full-duplex mode

# Change XYZ to the UID of your RS485 Bricklet

setup:
    # Enable full-duplex mode
    publish '{"baudrate": 115200, "parity": "none", "stopbits": "1", "wordlength": "8", "duplex": "full"}' to tinkerforge/request/rs485_bricklet/XYZ/set_rs485_configuration 
    
    # Handle incoming read callbacks
    subscribe to tinkerforge/callback/rs485_bricklet/XYZ/read # Received messages contain the message as string
    publish '{"register": true}' to tinkerforge/register/rs485_bricklet/XYZ/read # Register read callback
    
    # Enable read callback
    publish '' to tinkerforge/request/rs485_bricklet/XYZ/enable_read_callback 
    
    # Send test message
    publish '{"message": "test"}' to tinkerforge/request/rs485_bricklet/XYZ/write

Modbus Master

Download (example-modbus-master.txt)

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# Change XYZ to the UID of your RS485 Bricklet

setup:
    # Set operating mode to Modbus RTU master
    publish '{"mode": "modbus_master_rtu"}' to tinkerforge/request/rs485_bricklet/XYZ/set_mode 
    
    # Modbus specific configuration:
    # - slave address = 1 (unused in master mode)
    # - master request timeout = 1000ms
    publish '{"slave_address": 1, "master_request_timeout": 1000}' to tinkerforge/request/rs485_bricklet/XYZ/set_modbus_configuration 
    
    # Handle incoming Modbus master write single register response callbacks
    subscribe to tinkerforge/callback/rs485_bricklet/XYZ/modbus_master_write_single_register_response
        if a message arrives
            # message contains request_id as int and exception_code as int with symbols
            print request_id
            if exception_code != "Timeout
                print exception_code
            endif
        endif
    endsubscribe
    publish '{"register": true}' to tinkerforge/register/rs485_bricklet/XYZ/modbus_master_write_single_register_response
    
    # Write 65535 to register 42 of slave 17
    publish '{"slave_address": 17, "register_address": 42, "register_value": 65535}' to tinkerforge/request/rs485_bricklet/XYZ/modbus_master_write_single_register 

Modbus Slave

Download (example-modbus-slave.txt)

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# Change XYZ to the UID of your RS485 Bricklet

setup:
    # Set operating mode to Modbus RTU slave
    publish '{"mode": "modbus_slave_rtu"}' to tinkerforge/request/rs485_bricklet/XYZ/set_mode 
    
    # Modbus specific configuration:
    # - slave address = 17
    # - master request timeout = 0ms (unused in slave mode)
    publish '{"slave_address": 17, "master_request_timeout": 0}' to tinkerforge/request/rs485_bricklet/XYZ/set_modbus_configuration 
    
    # Handle incoming Modbus slave write single register request callbacks
    subscribe to tinkerforge/callback/rs485_bricklet/XYZ/modbus_slave_write_single_register_request
        if a message arrives            
            # message contains request_id as int, register_address as ant and register_value as int
            
            if registerAddress != 42
                print "Error: Invalid register address"
                publish '{"request_id": request_id, "exception_code": "IllegalDataAddress"}' to tinkerforge/request/rs485_bricklet/XYZ/modbus_slave_report_exception
            elseif
                publish '{"request_id": request_id}' to tinkerforge/request/rs485_bricklet/XYZ/modbus_slave_answer_write_single_register_request
            endif
        endif
    endsubscribe
    
    publish '{"register": true}' to tinkerforge/register/rs485_bricklet/XYZ/modbus_slave_write_single_register_request

API

All published payload to an from the MQTT bindings is in the JSON format.

If an error occures, the bindings publish a JSON object containing the error message as attribute "_ERROR". It is published on the corresponding response topic: .../response/... for .../request/... and .../callback/... for .../register/....

Basic Functions

request/rs485_bricklet/<UID>/write
Request payload:
 
  • message -- string
Response payload:
 
  • message_written -- int

Writes characters to the RS485 interface. The characters can be binary data, ASCII or similar is not necessary.

The return value is the number of characters that were written.

See request/rs485_bricklet/<UID>/set_rs485_configuration for configuration possibilities regarding baudrate, parity and so on.

request/rs485_bricklet/<UID>/read
Request payload:
 
  • length -- int
Response payload:
 
  • message -- string

Returns up to length characters from receive buffer.

Instead of polling with this function, you can also use callbacks. But note that this function will return available data only when the read callback is disabled. See request/rs485_bricklet/<UID>/enable_read_callback and register/rs485_bricklet/<UID>/read callback.

request/rs485_bricklet/<UID>/set_rs485_configuration
Request payload:
 
  • baudrate -- int
  • parity -- int (has symbols)
  • stopbits -- int (has symbols)
  • wordlength -- int (has symbols)
  • duplex -- int (has symbols)

Sets the configuration for the RS485 communication. Available options:

  • Baudrate between 100 and 2000000 baud.
  • Parity of none, odd or even.
  • Stopbits can be 1 or 2.
  • Word length of 5 to 8.
  • Half- or Full-Duplex.

The default is: 115200 baud, parity none, 1 stop bit, word length 8, half duplex.

The following symbols are available for this function:

for parity:

  • "None" = 0
  • "Odd" = 1
  • "Even" = 2

for stopbits:

  • "1" = 1
  • "2" = 2

for wordlength:

  • "5" = 5
  • "6" = 6
  • "7" = 7
  • "8" = 8

for duplex:

  • "Half" = 0
  • "Full" = 1
request/rs485_bricklet/<UID>/get_rs485_configuration
Response payload:
 
  • baudrate -- int
  • parity -- int (has symbols)
  • stopbits -- int (has symbols)
  • wordlength -- int (has symbols)
  • duplex -- int (has symbols)

Returns the configuration as set by request/rs485_bricklet/<UID>/set_rs485_configuration.

The following symbols are available for this function:

for parity:

  • "None" = 0
  • "Odd" = 1
  • "Even" = 2

for stopbits:

  • "1" = 1
  • "2" = 2

for wordlength:

  • "5" = 5
  • "6" = 6
  • "7" = 7
  • "8" = 8

for duplex:

  • "Half" = 0
  • "Full" = 1
request/rs485_bricklet/<UID>/set_modbus_configuration
Request payload:
 
  • slave_address -- int
  • master_request_timeout -- int

Sets the configuration for the RS485 Modbus communication. Available options:

  • Slave Address: Address to be used as the Modbus slave address in Modbus slave mode. Valid Modbus slave address range is 1 to 247.
  • Master Request Timeout: Specifies how long the master should wait for a response from a slave in milliseconds when in Modbus master mode.

The default is: Slave Address = 1 and Master Request Timeout = 1000 milliseconds (1 second).

request/rs485_bricklet/<UID>/get_modbus_configuration
Response payload:
 
  • slave_address -- int
  • master_request_timeout -- int

Returns the configuration as set by request/rs485_bricklet/<UID>/set_modbus_configuration.

request/rs485_bricklet/<UID>/set_mode
Request payload:
 
  • mode -- int (has symbols)

Sets the mode of the Bricklet in which it operates. Available options are

  • RS485,
  • Modbus Master RTU and
  • Modbus Slave RTU.

The default is: RS485 mode.

The following symbols are available for this function:

for mode:

  • "RS485" = 0
  • "ModbusMasterRTU" = 1
  • "ModbusSlaveRTU" = 2
request/rs485_bricklet/<UID>/get_mode
Response payload:
 
  • mode -- int (has symbols)

Returns the configuration as set by request/rs485_bricklet/<UID>/set_mode.

The following symbols are available for this function:

for mode:

  • "RS485" = 0
  • "ModbusMasterRTU" = 1
  • "ModbusSlaveRTU" = 2

Advanced Functions

request/rs485_bricklet/<UID>/set_communication_led_config
Request payload:
 
  • config -- int (has symbols)

Sets the communication LED configuration. By default the LED shows RS485 communication traffic by flickering.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is off.

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowCommunication" = 3
request/rs485_bricklet/<UID>/get_communication_led_config
Response payload:
 
  • config -- int (has symbols)

Returns the configuration as set by request/rs485_bricklet/<UID>/set_communication_led_config

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowCommunication" = 3
request/rs485_bricklet/<UID>/set_error_led_config
Request payload:
 
  • config -- int (has symbols)

Sets the error LED configuration.

By default the error LED turns on if there is any error (see register/rs485_bricklet/<UID>/error_count callback). If you call this function with the SHOW ERROR option again, the LED will turn off until the next error occurs.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is off.

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowError" = 3
request/rs485_bricklet/<UID>/get_error_led_config
Response payload:
 
  • config -- int (has symbols)

Returns the configuration as set by request/rs485_bricklet/<UID>/set_error_led_config.

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowError" = 3
request/rs485_bricklet/<UID>/set_buffer_config
Request payload:
 
  • send_buffer_size -- int
  • receive_buffer_size -- int

Sets the send and receive buffer size in byte. In sum there is 10240 byte (10kb) buffer available and the minimum buffer size is 1024 byte (1kb) for both.

The current buffer content is lost if this function is called.

The send buffer holds data that was given by request/rs485_bricklet/<UID>/write and could not be written yet. The receive buffer holds data that is received through RS485 but could not yet be send to the user, either by request/rs485_bricklet/<UID>/read or through register/rs485_bricklet/<UID>/read callback.

The default configuration is 5120 byte (5kb) per buffer.

request/rs485_bricklet/<UID>/get_buffer_config
Response payload:
 
  • send_buffer_size -- int
  • receive_buffer_size -- int

Returns the buffer configuration as set by request/rs485_bricklet/<UID>/set_buffer_config.

request/rs485_bricklet/<UID>/get_buffer_status
Response payload:
 
  • send_buffer_used -- int
  • receive_buffer_used -- int

Returns the currently used bytes for the send and received buffer.

See request/rs485_bricklet/<UID>/set_buffer_config for buffer size configuration.

request/rs485_bricklet/<UID>/get_error_count
Response payload:
 
  • overrun_error_count -- int
  • parity_error_count -- int

Returns the current number of overrun and parity errors.

request/rs485_bricklet/<UID>/get_modbus_common_error_count
Response payload:
 
  • timeout_error_count -- int
  • checksum_error_count -- int
  • frame_too_big_error_count -- int
  • illegal_function_error_count -- int
  • illegal_data_address_error_count -- int
  • illegal_data_value_error_count -- int
  • slave_device_failure_error_count -- int

Returns the current number of errors occurred in Modbus mode.

  • Timeout Error Count: Number of timeouts occurred.
  • Checksum Error Count: Number of failures due to Modbus frame CRC16 checksum mismatch.
  • Frame Too Big Error Count: Number of times frames were rejected because they exceeded maximum Modbus frame size which is 256 bytes.
  • Illegal Function Error Count: Number of errors when an unimplemented or illegal function is requested. This corresponds to Modbus exception code 1.
  • Illegal Data Address Error Count: Number of errors due to invalid data address. This corresponds to Modbus exception code 2.
  • Illegal Data Value Error Count: Number of errors due to invalid data value. This corresponds to Modbus exception code 3.
  • Slave Device Failure Error Count: Number of errors occurred on the slave device which were unrecoverable. This corresponds to Modbus exception code 4.
request/rs485_bricklet/<UID>/modbus_slave_report_exception
Request payload:
 
  • request_id -- int
  • exception_code -- int (has symbols)

In Modbus slave mode this function can be used to report a Modbus exception for a Modbus master request.

  • Request ID: Request ID of the request received by the slave.
  • Exception Code: Modbus exception code to report to the Modbus master.

The following symbols are available for this function:

for exception_code:

  • "Timeout" = -1
  • "Success" = 0
  • "IllegalFunction" = 1
  • "IllegalDataAddress" = 2
  • "IllegalDataValue" = 3
  • "SlaveDeviceFailure" = 4
  • "Acknowledge" = 5
  • "SlaveDeviceBusy" = 6
  • "MemoryParityError" = 8
  • "GatewayPathUnavailable" = 10
  • "GatewayTargetDeviceFailedToRespond" = 11
request/rs485_bricklet/<UID>/modbus_slave_answer_read_coils_request
Request payload:
 
  • request_id -- int
  • coils -- [bool,...]

In Modbus slave mode this function can be used to answer a master request to read coils.

  • Request ID: Request ID of the corresponding request that is being answered.
  • Coils: Data that is to be sent to the Modbus master for the corresponding request.

This function must be called from the register/rs485_bricklet/<UID>/modbus_slave_read_coils_request callback with the Request ID as provided by the argument of the callback.

request/rs485_bricklet/<UID>/modbus_master_read_coils
Request payload:
 
  • slave_address -- int
  • starting_address -- int
  • count -- int
Response payload:
 
  • request_id -- int

In Modbus master mode this function can be used to read coils from a slave. This function creates a Modbus function code 1 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Starting address of the read.
  • Count: Number of coils to read.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the register/rs485_bricklet/<UID>/modbus_master_read_coils_response callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

request/rs485_bricklet/<UID>/modbus_slave_answer_read_holding_registers_request
Request payload:
 
  • request_id -- int
  • holding_registers -- [int,...]

In Modbus slave mode this function can be used to answer a master request to read holding registers.

  • Request ID: Request ID of the corresponding request that is being answered.
  • Holding Registers: Data that is to be sent to the Modbus master for the corresponding request.

This function must be called from the register/rs485_bricklet/<UID>/modbus_slave_read_holding_registers_request callback with the Request ID as provided by the argument of the callback.

request/rs485_bricklet/<UID>/modbus_master_read_holding_registers
Request payload:
 
  • slave_address -- int
  • starting_address -- int
  • count -- int
Response payload:
 
  • request_id -- int

In Modbus master mode this function can be used to read holding registers from a slave. This function creates a Modbus function code 3 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Starting address of the read.
  • Count: Number of holding registers to read.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the register/rs485_bricklet/<UID>/modbus_master_read_holding_registers_response callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

request/rs485_bricklet/<UID>/modbus_slave_answer_write_single_coil_request
Request payload:
 
  • request_id -- int

In Modbus slave mode this function can be used to answer a master request to write a single coil.

  • Request ID: Request ID of the corresponding request that is being answered.

This function must be called from the register/rs485_bricklet/<UID>/modbus_slave_write_single_coil_request callback with the Request ID as provided by the arguments of the callback.

request/rs485_bricklet/<UID>/modbus_master_write_single_coil
Request payload:
 
  • slave_address -- int
  • coil_address -- int
  • coil_value -- bool
Response payload:
 
  • request_id -- int

In Modbus master mode this function can be used to write a single coil of a slave. This function creates a Modbus function code 5 request.

  • Slave Address: Address of the target Modbus slave.
  • Coil Address: Address of the coil.
  • Coil Value: Value to be written.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the register/rs485_bricklet/<UID>/modbus_master_write_single_coil_response callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

request/rs485_bricklet/<UID>/modbus_slave_answer_write_single_register_request
Request payload:
 
  • request_id -- int

In Modbus slave mode this function can be used to answer a master request to write a single register.

  • Request ID: Request ID of the corresponding request that is being answered.

This function must be called from the register/rs485_bricklet/<UID>/modbus_slave_write_single_register_request callback with the Request ID, Register Address and Register Value as provided by the arguments of the callback.

request/rs485_bricklet/<UID>/modbus_master_write_single_register
Request payload:
 
  • slave_address -- int
  • register_address -- int
  • register_value -- int
Response payload:
 
  • request_id -- int

In Modbus master mode this function can be used to write a single register of a slave. This function creates a Modbus function code 6 request.

  • Slave Address: Address of the target Modbus slave.
  • Register Address: Address of the register.
  • Register Value: Value to be written.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the register/rs485_bricklet/<UID>/modbus_master_write_single_register_response callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

request/rs485_bricklet/<UID>/modbus_slave_answer_write_multiple_coils_request
Request payload:
 
  • request_id -- int

In Modbus slave mode this function can be used to answer a master request to write multiple coils.

  • Request ID: Request ID of the corresponding request that is being answered.

This function must be called from the register/rs485_bricklet/<UID>/modbus_slave_write_multiple_coils_request callback with the Request ID of the callback.

request/rs485_bricklet/<UID>/modbus_master_write_multiple_coils
Request payload:
 
  • slave_address -- int
  • starting_address -- int
  • coils -- [bool,...]
Response payload:
 
  • request_id -- int

In Modbus master mode this function can be used to write multiple coils of a slave. This function creates a Modbus function code 15 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Starting address of the write.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the register/rs485_bricklet/<UID>/modbus_master_write_multiple_coils_response callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

request/rs485_bricklet/<UID>/modbus_slave_answer_write_multiple_registers_request
Request payload:
 
  • request_id -- int

In Modbus slave mode this function can be used to answer a master request to write multiple registers.

  • Request ID: Request ID of the corresponding request that is being answered.

This function must be called from the register/rs485_bricklet/<UID>/modbus_slave_write_multiple_registers_request callback with the Request ID of the callback.

request/rs485_bricklet/<UID>/modbus_master_write_multiple_registers
Request payload:
 
  • slave_address -- int
  • starting_address -- int
  • registers -- [int,...]
Response payload:
 
  • request_id -- int

In Modbus master mode this function can be used to write multiple registers of a slave. This function creates a Modbus function code 16 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Starting Address of the write.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the register/rs485_bricklet/<UID>/modbus_master_write_multiple_registers_response callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

request/rs485_bricklet/<UID>/modbus_slave_answer_read_discrete_inputs_request
Request payload:
 
  • request_id -- int
  • discrete_inputs -- [bool,...]

In Modbus slave mode this function can be used to answer a master request to read discrete inputs.

  • Request ID: Request ID of the corresponding request that is being answered.
  • Discrete Inputs: Data that is to be sent to the Modbus master for the corresponding request.

This function must be called from the register/rs485_bricklet/<UID>/modbus_slave_read_discrete_inputs_request callback with the Request ID as provided by the argument of the callback.

request/rs485_bricklet/<UID>/modbus_master_read_discrete_inputs
Request payload:
 
  • slave_address -- int
  • starting_address -- int
  • count -- int
Response payload:
 
  • request_id -- int

In Modbus master mode this function can be used to read discrete inputs from a slave. This function creates a Modbus function code 2 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Starting address of the read.
  • Count: Number of discrete inputs to read.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the register/rs485_bricklet/<UID>/modbus_master_read_discrete_inputs_response callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

request/rs485_bricklet/<UID>/modbus_slave_answer_read_input_registers_request
Request payload:
 
  • request_id -- int
  • input_registers -- [int,...]

In Modbus slave mode this function can be used to answer a master request to read input registers.

  • Request ID: Request ID of the corresponding request that is being answered.
  • Input Registers: Data that is to be sent to the Modbus master for the corresponding request.

This function must be called from the register/rs485_bricklet/<UID>/modbus_slave_read_input_registers_request callback with the Request ID as provided by the argument of the callback.

request/rs485_bricklet/<UID>/modbus_master_read_input_registers
Request payload:
 
  • slave_address -- int
  • starting_address -- int
  • count -- int
Response payload:
 
  • request_id -- int

In Modbus master mode this function can be used to read input registers from a slave. This function creates a Modbus function code 4 request.

  • Slave Address: Address of the target Modbus slave.
  • Starting Address: Starting address of the read.
  • Count: Number of input registers to read.

Upon success the function will return a non-zero request ID which will represent the current request initiated by the Modbus master. In case of failure the returned request ID will be 0.

When successful this function will also invoke the register/rs485_bricklet/<UID>/modbus_master_read_input_registers_response callback. In this callback the Request ID provided by the callback argument must be matched with the Request ID returned from this function to verify that the callback is indeed for a particular request.

request/rs485_bricklet/<UID>/get_spitfp_error_count
Response payload:
 
  • error_count_ack_checksum -- int
  • error_count_message_checksum -- int
  • error_count_frame -- int
  • error_count_overflow -- int

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

request/rs485_bricklet/<UID>/set_bootloader_mode
Request payload:
 
  • mode -- int (has symbols)
Response payload:
 
  • status -- int (has symbols)

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following symbols are available for this function:

for mode:

  • "Bootloader" = 0
  • "Firmware" = 1
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4

for status:

  • "OK" = 0
  • "InvalidMode" = 1
  • "NoChange" = 2
  • "EntryFunctionNotPresent" = 3
  • "DeviceIdentifierIncorrect" = 4
  • "CRCMismatch" = 5
request/rs485_bricklet/<UID>/get_bootloader_mode
Response payload:
 
  • mode -- int (has symbols)

Returns the current bootloader mode, see request/rs485_bricklet/<UID>/set_bootloader_mode.

The following symbols are available for this function:

for mode:

  • "Bootloader" = 0
  • "Firmware" = 1
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4
request/rs485_bricklet/<UID>/set_write_firmware_pointer
Request payload:
 
  • pointer -- int

Sets the firmware pointer for request/rs485_bricklet/<UID>/write_firmware. The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

request/rs485_bricklet/<UID>/write_firmware
Request payload:
 
  • data -- [int,... (x64)]
Response payload:
 
  • status -- int

Writes 64 Bytes of firmware at the position as written by request/rs485_bricklet/<UID>/set_write_firmware_pointer before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

request/rs485_bricklet/<UID>/set_status_led_config
Request payload:
 
  • config -- int (has symbols)

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/rs485_bricklet/<UID>/get_status_led_config
Response payload:
 
  • config -- int (has symbols)

Returns the configuration as set by request/rs485_bricklet/<UID>/set_status_led_config

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/rs485_bricklet/<UID>/get_chip_temperature
Response payload:
 
  • temperature -- int

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

request/rs485_bricklet/<UID>/reset

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

request/rs485_bricklet/<UID>/write_uid
Request payload:
 
  • uid -- int

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

request/rs485_bricklet/<UID>/read_uid
Response payload:
 
  • uid -- int

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

request/rs485_bricklet/<UID>/get_identity
Response payload:
 
  • uid -- string
  • connected_uid -- string
  • position -- string
  • hardware_version -- [int,int,int]
  • firmware_version -- [int,int,int]
  • device_identifier -- int (has symbols)
  • _display_name -- string

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c' or 'd'.

The device identifier numbers can be found here. If symbolic output is not disabled, the device identifier is mapped to the corresponding name in the format used in topics.

The display name contains the RS485's name in a human readable form.

Callback Configuration Functions

request/rs485_bricklet/<UID>/enable_read_callback

Enables the register/rs485_bricklet/<UID>/read callback.

By default the callback is disabled.

request/rs485_bricklet/<UID>/disable_read_callback

Disables the register/rs485_bricklet/<UID>/read callback.

By default the callback is disabled.

request/rs485_bricklet/<UID>/is_read_callback_enabled
Response payload:
 
  • enabled -- bool

Returns true if the register/rs485_bricklet/<UID>/read callback is enabled, false otherwise.

request/rs485_bricklet/<UID>/enable_error_count_callback

Enables the register/rs485_bricklet/<UID>/error_count callback.

By default the callback is disabled.

request/rs485_bricklet/<UID>/disable_error_count_callback

Disables the register/rs485_bricklet/<UID>/error_count callback.

By default the callback is disabled.

request/rs485_bricklet/<UID>/is_error_count_callback_enabled
Response payload:
 
  • enabled -- bool

Returns true if the register/rs485_bricklet/<UID>/error_count callback is enabled, false otherwise.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding .../register/... topic and an optional suffix. This suffix can be used to deregister the callback later.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

register/rs485_bricklet/<UID>/read
Request payload:
 
  • register -- bool
Response payload:
 
  • message -- string

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/read[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/read[/<SUFFIX>] topic for each registered suffix.

This callback is called if new data is available.

To enable this callback, use request/rs485_bricklet/<UID>/enable_read_callback.

register/rs485_bricklet/<UID>/error_count
Request payload:
 
  • register -- bool
Response payload:
 
  • overrun_error_count -- int
  • parity_error_count -- int

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/error_count[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/error_count[/<SUFFIX>] topic for each registered suffix.

This callback is called if a new error occurs. It returns the current overrun and parity error count.

register/rs485_bricklet/<UID>/modbus_slave_read_coils_request
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • starting_address -- int
  • count -- int

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_slave_read_coils_request[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_slave_read_coils_request[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to read coils. The callback payload members are request ID of the request, the starting address and the number of coils to be read as received by the request.

To send a response of this request use request/rs485_bricklet/<UID>/modbus_slave_answer_read_coils_request.

register/rs485_bricklet/<UID>/modbus_master_read_coils_response
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • exception_code -- int (has symbols)
  • coils -- [bool,...]

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_master_read_coils_response[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_master_read_coils_response[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus master mode when the master receives a valid response of a request to read coils.

The callback payload members are request ID of the request, exception code of the response and the data as received by the response.

Any non-zero exception code indicates a problem. If the exception code is greater than zero then the number represents a Modbus exception code. If it is less than zero then it represents other errors. For example, -1 indicates that the request timed out or that the master did not receive any valid response of the request within the master request timeout period as set by request/rs485_bricklet/<UID>/set_modbus_configuration.

The following symbols are available for this function:

for exception_code:

  • "Timeout" = -1
  • "Success" = 0
  • "IllegalFunction" = 1
  • "IllegalDataAddress" = 2
  • "IllegalDataValue" = 3
  • "SlaveDeviceFailure" = 4
  • "Acknowledge" = 5
  • "SlaveDeviceBusy" = 6
  • "MemoryParityError" = 8
  • "GatewayPathUnavailable" = 10
  • "GatewayTargetDeviceFailedToRespond" = 11
register/rs485_bricklet/<UID>/modbus_slave_read_holding_registers_request
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • starting_address -- int
  • count -- int

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_slave_read_holding_registers_request[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_slave_read_holding_registers_request[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to read holding registers. The callback payload members are request ID of the request, the starting address and the number of holding registers to be read as received by the request.

To send a response of this request use request/rs485_bricklet/<UID>/modbus_slave_answer_read_holding_registers_request.

register/rs485_bricklet/<UID>/modbus_master_read_holding_registers_response
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • exception_code -- int (has symbols)
  • holding_registers -- [int,...]

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_master_read_holding_registers_response[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_master_read_holding_registers_response[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus master mode when the master receives a valid response of a request to read holding registers.

The callback payload members are request ID of the request, exception code of the response and the data as received by the response.

Any non-zero exception code indicates a problem. If the exception code is greater than zero then the number represents a Modbus exception code. If it is less than zero then it represents other errors. For example, -1 indicates that the request timed out or that the master did not receive any valid response of the request within the master request timeout period as set by request/rs485_bricklet/<UID>/set_modbus_configuration.

The following symbols are available for this function:

for exception_code:

  • "Timeout" = -1
  • "Success" = 0
  • "IllegalFunction" = 1
  • "IllegalDataAddress" = 2
  • "IllegalDataValue" = 3
  • "SlaveDeviceFailure" = 4
  • "Acknowledge" = 5
  • "SlaveDeviceBusy" = 6
  • "MemoryParityError" = 8
  • "GatewayPathUnavailable" = 10
  • "GatewayTargetDeviceFailedToRespond" = 11
register/rs485_bricklet/<UID>/modbus_slave_write_single_coil_request
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • coil_address -- int
  • coil_value -- bool

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_slave_write_single_coil_request[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_slave_write_single_coil_request[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to write a single coil. The callback payload members are request ID of the request, the coil address and the value of coil to be written as received by the request.

To send a response of this request use request/rs485_bricklet/<UID>/modbus_slave_answer_write_single_coil_request.

register/rs485_bricklet/<UID>/modbus_master_write_single_coil_response
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • exception_code -- int (has symbols)

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_master_write_single_coil_response[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_master_write_single_coil_response[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus master mode when the master receives a valid response of a request to write a single coil.

The callback payload members are request ID of the request and exception code of the response.

Any non-zero exception code indicates a problem. If the exception code is greater than zero then the number represents a Modbus exception code. If it is less than zero then it represents other errors. For example, -1 indicates that the request timed out or that the master did not receive any valid response of the request within the master request timeout period as set by request/rs485_bricklet/<UID>/set_modbus_configuration.

The following symbols are available for this function:

for exception_code:

  • "Timeout" = -1
  • "Success" = 0
  • "IllegalFunction" = 1
  • "IllegalDataAddress" = 2
  • "IllegalDataValue" = 3
  • "SlaveDeviceFailure" = 4
  • "Acknowledge" = 5
  • "SlaveDeviceBusy" = 6
  • "MemoryParityError" = 8
  • "GatewayPathUnavailable" = 10
  • "GatewayTargetDeviceFailedToRespond" = 11
register/rs485_bricklet/<UID>/modbus_slave_write_single_register_request
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • register_address -- int
  • register_value -- int

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_slave_write_single_register_request[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_slave_write_single_register_request[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to write a single register. The callback payload members are request ID of the request, the register address and the register value to be written as received by the request.

To send a response of this request use request/rs485_bricklet/<UID>/modbus_slave_answer_write_single_register_request.

register/rs485_bricklet/<UID>/modbus_master_write_single_register_response
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • exception_code -- int (has symbols)

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_master_write_single_register_response[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_master_write_single_register_response[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus master mode when the master receives a valid response of a request to write a single register.

The callback payload members are request ID of the request and exception code of the response.

Any non-zero exception code indicates a problem. If the exception code is greater than zero then the number represents a Modbus exception code. If it is less than zero then it represents other errors. For example, -1 indicates that the request timed out or that the master did not receive any valid response of the request within the master request timeout period as set by request/rs485_bricklet/<UID>/set_modbus_configuration.

The following symbols are available for this function:

for exception_code:

  • "Timeout" = -1
  • "Success" = 0
  • "IllegalFunction" = 1
  • "IllegalDataAddress" = 2
  • "IllegalDataValue" = 3
  • "SlaveDeviceFailure" = 4
  • "Acknowledge" = 5
  • "SlaveDeviceBusy" = 6
  • "MemoryParityError" = 8
  • "GatewayPathUnavailable" = 10
  • "GatewayTargetDeviceFailedToRespond" = 11
register/rs485_bricklet/<UID>/modbus_slave_write_multiple_coils_request
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • starting_address -- int
  • coils -- [bool,...]

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_slave_write_multiple_coils_request[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_slave_write_multiple_coils_request[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to write multiple coils. The callback payload members are request ID of the request, the starting address and the data to be written as received by the request.

To send a response of this request use request/rs485_bricklet/<UID>/modbus_slave_answer_write_multiple_coils_request.

register/rs485_bricklet/<UID>/modbus_master_write_multiple_coils_response
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • exception_code -- int (has symbols)

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_master_write_multiple_coils_response[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_master_write_multiple_coils_response[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus master mode when the master receives a valid response of a request to read coils.

The callback payload members are request ID of the request and exception code of the response.

Any non-zero exception code indicates a problem. If the exception code is greater than zero then the number represents a Modbus exception code. If it is less than zero then it represents other errors. For example, -1 indicates that the request timedout or that the master did not receive any valid response of the request within the master request timeout period as set by request/rs485_bricklet/<UID>/set_modbus_configuration.

The following symbols are available for this function:

for exception_code:

  • "Timeout" = -1
  • "Success" = 0
  • "IllegalFunction" = 1
  • "IllegalDataAddress" = 2
  • "IllegalDataValue" = 3
  • "SlaveDeviceFailure" = 4
  • "Acknowledge" = 5
  • "SlaveDeviceBusy" = 6
  • "MemoryParityError" = 8
  • "GatewayPathUnavailable" = 10
  • "GatewayTargetDeviceFailedToRespond" = 11
register/rs485_bricklet/<UID>/modbus_slave_write_multiple_registers_request
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • starting_address -- int
  • registers -- [int,...]

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_slave_write_multiple_registers_request[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_slave_write_multiple_registers_request[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to write multiple registers. The callback payload members are request ID of the request, the starting address and the data to be written as received by the request.

To send a response of this request use request/rs485_bricklet/<UID>/modbus_slave_answer_write_multiple_registers_request.

register/rs485_bricklet/<UID>/modbus_master_write_multiple_registers_response
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • exception_code -- int (has symbols)

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_master_write_multiple_registers_response[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_master_write_multiple_registers_response[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus master mode when the master receives a valid response of a request to write multiple registers.

The callback payload members are request ID of the request and exception code of the response.

Any non-zero exception code indicates a problem. If the exception code is greater than zero then the number represents a Modbus exception code. If it is less than zero then it represents other errors. For example, -1 indicates that the request timedout or that the master did not receive any valid response of the request within the master request timeout period as set by request/rs485_bricklet/<UID>/set_modbus_configuration.

The following symbols are available for this function:

for exception_code:

  • "Timeout" = -1
  • "Success" = 0
  • "IllegalFunction" = 1
  • "IllegalDataAddress" = 2
  • "IllegalDataValue" = 3
  • "SlaveDeviceFailure" = 4
  • "Acknowledge" = 5
  • "SlaveDeviceBusy" = 6
  • "MemoryParityError" = 8
  • "GatewayPathUnavailable" = 10
  • "GatewayTargetDeviceFailedToRespond" = 11
register/rs485_bricklet/<UID>/modbus_slave_read_discrete_inputs_request
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • starting_address -- int
  • count -- int

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_slave_read_discrete_inputs_request[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_slave_read_discrete_inputs_request[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to read discrete inputs. The callback payload members are request ID of the request, the starting address and the number of discrete inputs to be read as received by the request.

To send a response of this request use request/rs485_bricklet/<UID>/modbus_slave_answer_read_discrete_inputs_request.

register/rs485_bricklet/<UID>/modbus_master_read_discrete_inputs_response
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • exception_code -- int (has symbols)
  • discrete_inputs -- [bool,...]

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_master_read_discrete_inputs_response[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_master_read_discrete_inputs_response[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus master mode when the master receives a valid response of a request to read discrete inputs.

The callback payload members are request ID of the request, exception code of the response and the data as received by the response.

Any non-zero exception code indicates a problem. If the exception code is greater than zero then the number represents a Modbus exception code. If it is less than zero then it represents other errors. For example, -1 indicates that the request timedout or that the master did not receive any valid response of the request within the master request timeout period as set by request/rs485_bricklet/<UID>/set_modbus_configuration.

The following symbols are available for this function:

for exception_code:

  • "Timeout" = -1
  • "Success" = 0
  • "IllegalFunction" = 1
  • "IllegalDataAddress" = 2
  • "IllegalDataValue" = 3
  • "SlaveDeviceFailure" = 4
  • "Acknowledge" = 5
  • "SlaveDeviceBusy" = 6
  • "MemoryParityError" = 8
  • "GatewayPathUnavailable" = 10
  • "GatewayTargetDeviceFailedToRespond" = 11
register/rs485_bricklet/<UID>/modbus_slave_read_input_registers_request
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • starting_address -- int
  • count -- int

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_slave_read_input_registers_request[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_slave_read_input_registers_request[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus slave mode when the slave receives a valid request from a Modbus master to read input registers. The callback payload members are request ID of the request, the starting address and the number of input registers to be read as received by the request.

To send a response of this request use request/rs485_bricklet/<UID>/modbus_slave_answer_read_input_registers_request.

register/rs485_bricklet/<UID>/modbus_master_read_input_registers_response
Request payload:
 
  • register -- bool
Response payload:
 
  • request_id -- int
  • exception_code -- int (has symbols)
  • input_registers -- [int,...]

A callback can be registered for this event by publishing to the .../register/rs485_bricklet/<UID>/modbus_master_read_input_registers_response[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/rs485_bricklet/<UID>/modbus_master_read_input_registers_response[/<SUFFIX>] topic for each registered suffix.

This callback is called only in Modbus master mode when the master receives a valid response of a request to read input registers.

The callback payload members are request ID of the request, exception code of the response and the data as received by the response.

Any non-zero exception code indicates a problem. If the exception code is greater than zero then the number represents a Modbus exception code. If it is less than zero then it represents other errors. For example, -1 indicates that the request timedout or that the master did not receive any valid response of the request within the master request timeout period as set by request/rs485_bricklet/<UID>/set_modbus_configuration.

The following symbols are available for this function:

for exception_code:

  • "Timeout" = -1
  • "Success" = 0
  • "IllegalFunction" = 1
  • "IllegalDataAddress" = 2
  • "IllegalDataValue" = 3
  • "SlaveDeviceFailure" = 4
  • "Acknowledge" = 5
  • "SlaveDeviceBusy" = 6
  • "MemoryParityError" = 8
  • "GatewayPathUnavailable" = 10
  • "GatewayTargetDeviceFailedToRespond" = 11