Shell - Industrial Dual 0-20mA Bricklet

This is the description of the Shell API bindings for the Industrial Dual 0-20mA Bricklet. General information and technical specifications for the Industrial Dual 0-20mA Bricklet are summarized in its hardware description.

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

Examples

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

Simple

Download (example-simple.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Industrial Dual 0-20mA Bricklet

# Get current current from sensor 1
tinkerforge call industrial-dual-0-20ma-bricklet $uid get-current 1

Callback

Download (example-callback.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Industrial Dual 0-20mA Bricklet

# Handle incoming current callbacks
tinkerforge dispatch industrial-dual-0-20ma-bricklet $uid current &

# Set period for current (sensor 1) callback to 1s (1000ms)
# Note: The current (sensor 1) callback is only called every second
#       if the current (sensor 1) has changed since the last call!
tinkerforge call industrial-dual-0-20ma-bricklet $uid set-current-callback-period 1 1000

echo "Press key to exit"; read dummy

kill -- -$$ # Stop callback dispatch in background

Threshold

Download (example-threshold.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Industrial Dual 0-20mA Bricklet

# Get threshold callbacks with a debounce time of 10 seconds (10000ms)
tinkerforge call industrial-dual-0-20ma-bricklet $uid set-debounce-period 10000

# Handle incoming current reached callbacks
tinkerforge dispatch industrial-dual-0-20ma-bricklet $uid current-reached &

# Configure threshold for current (sensor 1) "greater than 10 mA"
tinkerforge call industrial-dual-0-20ma-bricklet $uid set-current-callback-threshold 1 threshold-option-greater 10000000 0

echo "Press key to exit"; read dummy

kill -- -$$ # Stop callback dispatch in background

API

Possible exit codes for all tinkerforge commands are:

  • 1: interrupted (ctrl+c)
  • 2: syntax error
  • 21: Python 2.5 or newer is required
  • 22: Python argparse module is missing
  • 23: socket error
  • 24: other exception
  • 25: invalid placeholder in format string
  • 26: authentication error
  • 201: timeout occurred
  • 209: invalid argument value
  • 210: function is not supported
  • 211: unknown error

Two sensors can be connected to the Bricklet. Functions that are related directly to a sensor have a sensor parameter to specify one of the two sensors. Valid values for the sensor parameter are 0 and 1.

Command Structure

The common options of the call and dispatch commands are documented here. The specific command structure is shown below.

tinkerforge call industrial-dual-0-20ma-bricklet [<option>..] <uid> <function> [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The call command is used to call a function of the Industrial Dual 0-20mA Bricklet. It can take several options:

  • --help shows help for the specific call command and exits
  • --list-functions shows a list of known functions of the Industrial Dual 0-20mA Bricklet and exits
tinkerforge dispatch industrial-dual-0-20ma-bricklet [<option>..] <uid> <callback>
Parameters:
  • <uid> -- string
  • <callback> -- string

The dispatch command is used to dispatch a callback of the Industrial Dual 0-20mA Bricklet. It can take several options:

  • --help shows help for the specific dispatch command and exits
  • --list-callbacks shows a list of known callbacks of the Industrial Dual 0-20mA Bricklet and exits
tinkerforge call industrial-dual-0-20ma-bricklet <uid> <function> [<option>..] [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The <function> to be called can take different options depending of its kind. All functions can take the following options:

  • --help shows help for the specific function and exits

Getter functions can take the following options:

  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Setter functions can take the following options:

  • --expect-response requests response and waits for it

The --expect-response option for setter functions allows to detect timeouts and other error conditions calls of setters as well. The device will then send a response for this purpose. If this option is not given for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

tinkerforge dispatch industrial-dual-0-20ma-bricklet <uid> <callback> [<option>..]
Parameters:
  • <uid> -- string
  • <callback> -- string

The <callback> to be dispatched can take several options:

  • --help shows help for the specific callback and exits
  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Basic Functions

tinkerforge call industrial-dual-0-20ma-bricklet <uid> get-current <sensor>
Parameters:
  • <sensor> -- int
Output:
  • current -- int

Returns the current of the specified sensor (0 or 1). The value is in nA and between 0nA and 22505322nA (22.5mA).

It is possible to detect if an IEC 60381-1 compatible sensor is connected and if it works probably.

If the returned current is below 4mA, there is likely no sensor connected or the sensor may be defect. If the returned current is over 20mA, there might be a short circuit or the sensor may be defect.

If you want to get the current periodically, it is recommended to use the current callback and set the period with set-current-callback-period.

Advanced Functions

tinkerforge call industrial-dual-0-20ma-bricklet <uid> set-sample-rate <rate>
Parameters:
  • <rate> -- int (has symbols)
Output:

no output

Sets the sample rate to either 240, 60, 15 or 4 samples per second. The resolution for the rates is 12, 14, 16 and 18 bit respectively.

Value Description
0 240 samples per second, 12 bit resolution
1 60 samples per second, 14 bit resolution
2 15 samples per second, 16 bit resolution
3 4 samples per second, 18 bit resolution

The default value is 3 (4 samples per second with 18 bit resolution).

The following symbols are available for this function:

  • sample-rate-240-sps = 0, for <rate>
  • sample-rate-60-sps = 1, for <rate>
  • sample-rate-15-sps = 2, for <rate>
  • sample-rate-4-sps = 3, for <rate>
tinkerforge call industrial-dual-0-20ma-bricklet <uid> get-sample-rate
Output:
  • rate -- int (has symbols)

Returns the sample rate as set by set-sample-rate.

The following symbols are available for this function:

  • sample-rate-240-sps = 0, for rate
  • sample-rate-60-sps = 1, for rate
  • sample-rate-15-sps = 2, for rate
  • sample-rate-4-sps = 3, for rate
tinkerforge call industrial-dual-0-20ma-bricklet <uid> get-identity
Output:
  • uid -- string
  • connected-uid -- string
  • position -- char
  • hardware-version -- int,int,int
  • firmware-version -- int,int,int
  • device-identifier -- int (has symbols)

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

Callback Configuration Functions

tinkerforge call industrial-dual-0-20ma-bricklet <uid> set-current-callback-period <sensor> <period>
Parameters:
  • <sensor> -- int
  • <period> -- int
Output:

no output

Sets the period in ms with which the current callback is triggered periodically for the given sensor. A value of 0 turns the callback off.

The current callback is only triggered if the current has changed since the last triggering.

The default value is 0.

tinkerforge call industrial-dual-0-20ma-bricklet <uid> get-current-callback-period <sensor>
Parameters:
  • <sensor> -- int
Output:
  • period -- int

Returns the period as set by set-current-callback-period.

tinkerforge call industrial-dual-0-20ma-bricklet <uid> set-current-callback-threshold <sensor> <option> <min> <max>
Parameters:
  • <sensor> -- int
  • <option> -- char (has symbols)
  • <min> -- int
  • <max> -- int
Output:

no output

Sets the thresholds for the current-reached callback for the given sensor.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the current is outside the min and max values
'i' Callback is triggered when the current is inside the min and max values
'<' Callback is triggered when the current is smaller than the min value (max is ignored)
'>' Callback is triggered when the current is greater than the min value (max is ignored)

The default value is ('x', 0, 0).

The following symbols are available for this function:

  • threshold-option-off = x, for <option>
  • threshold-option-outside = o, for <option>
  • threshold-option-inside = i, for <option>
  • threshold-option-smaller = <, for <option>
  • threshold-option-greater = >, for <option>
tinkerforge call industrial-dual-0-20ma-bricklet <uid> get-current-callback-threshold <sensor>
Parameters:
  • <sensor> -- int
Output:
  • option -- char (has symbols)
  • min -- int
  • max -- int

Returns the threshold as set by set-current-callback-threshold.

The following symbols are available for this function:

  • threshold-option-off = x, for option
  • threshold-option-outside = o, for option
  • threshold-option-inside = i, for option
  • threshold-option-smaller = <, for option
  • threshold-option-greater = >, for option
tinkerforge call industrial-dual-0-20ma-bricklet <uid> set-debounce-period <debounce>
Parameters:
  • <debounce> -- int
Output:

no output

Sets the period in ms with which the threshold callback

is triggered, if the threshold

keeps being reached.

The default value is 100.

tinkerforge call industrial-dual-0-20ma-bricklet <uid> get-debounce-period
Output:
  • debounce -- int

Returns the debounce period as set by set-debounce-period.

Callbacks

Callbacks can be used to receive time critical or recurring data from the device:

tinkerforge dispatch industrial-dual-0-20ma-bricklet <uid> example

The available callbacks are described below.

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.

tinkerforge dispatch industrial-dual-0-20ma-bricklet <uid> current
Output:
  • sensor -- int
  • current -- int

This callback is triggered periodically with the period that is set by set-current-callback-period. The parameter is the current of the sensor.

The current callback is only triggered if the current has changed since the last triggering.

tinkerforge dispatch industrial-dual-0-20ma-bricklet <uid> current-reached
Output:
  • sensor -- int
  • current -- int

This callback is triggered when the threshold as set by set-current-callback-threshold is reached. The parameter is the current of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by set-debounce-period.