A Tango device server for controlling an alarm device via RaspberryPi's GPIO.
It will monitor a Tango attribute and start the alarm depending on the value.
You can monitor if the value is too high, too low or outside defined range.
The alarm signal is configurable as well.
It supports two levels of alarm with distinct signalling: warning and alarm.
It was originally designed to drive a piezoelectic buzzer, but it can be used for other devices, such as LEDs as well.
- Python 3.x (it should work on 2.7, but this was not tested)
- pytango 9.2+
RPi.GPIO
Note: If you run this DS under an user different than the default pi (e.g. tango, via Starter) make sure that this user is added to the gpio group!
To install, run sudo python setup.py install in the project's directory.
To run, use rpialarm <instance_name>.
The server is configured by following device properties:
| Property name | Description | Default value |
|---|---|---|
| gpio | GPIO pin (BCM mode) your alarm device is connected to | |
| monitor_attr | Tango attribute to be monitored | |
| polling_time | Monitor thread polling time (in seconds) | 0.2 |
and following expert mode attributes:
| Attribute name | Data type | Description |
|---|---|---|
| mode | str | Operation mode, can be on of LOW, HIGH or RANGE. In LOW mode the alarm is activated if the monitored attribute value falls below ones configured in low_* attributes. In HIGH mode the alarm is activated if the value raises above ones configured in high_* attributes. In RANGE mode the alarm is activated if the value falls outside range defined by low_* and high_* attributes. |
| low_alarm | float | Alarm threshold for LOW mode and lower alarm threshold for RANGE mode. |
| low_warning | float | Warning threshold for LOW mode and lower warning threshold for RANGE mode. |
| high_alarm | float | Alarm threshold for HIGH mode and upper alarm threshold for RANGE mode. |
| high_warning | float | Warning threshold for HIGH mode and upper warning threshold for RANGE mode. |
| alarm_conf | str | Configuration for alarm signal. It should be in the following format: <time_active>:<time_sleep>, e.g. 0.1:0.5. time_active is the time for which GPIO output will be held high (in seconds), then it will be held low for time_sleep (in seconds). This sequence will be repeated in a loop as long as the alarm condition is present. |
| warning_conf | str | Configuration for warning signal. The format is the same as in alarm_conf. |
Apart from configuration attributes described above there are the following read-only operator mode attributes:
| Attribute name | Data type | Description |
|---|---|---|
| alarm_flag | bool | Indicates that an alarm condition is present. |
| warning_flag | bool | Indicates that a warning condition is present. |
| test_flag | bool | Indicates that a test is active. |
| reset_flag | bool | Indicates that a reset has been issued for current alarm or warning. |
The server provides the following commands:
| Command name | Arguments | Description |
|---|---|---|
| test | str | Tests the alarm or warning signal (enables GPIO loop without alarm/warning condition present). It requires a string argument, one of ALARM or WARNING. The test can be stopped by reset command. |
| reset | Stops signalling the alarm/warning (stops GPIO loop) while the alarm/warning condition is still present. The alarm/warning flag attributes are not affected. Reset is in effect until the state changes (e.g. from warning to alarm, from alarm to OK, etc.). The reset command is also used to stop the test initiated with test command. |
This project is distributed under the GNU GPLv3 license. You can read the full license text in LICENSE file in project's directory.