add option to disable analog event publishing

config.ini

@@ -9,3 +9,4 @@ digitalInputTopicPrefix = dt1/di
 analogInputEventTopicPrefix = dt1/ai/event
 analogInputPeriodicTopicPrefix = dt1/ai/periodic
 analogInputPublishPeriod = 10.0
+disableAnalogInputEventPublishing = true

readme.md

@@ -0,0 +1,55 @@
+# DigitalTwin1
+## Digital twin for Beckhoff BK-9000 Modbus-TCP coupler (and compatible Wago device)
+
+
+### Overview 
+
+This tool connects to a Modbus-TCP coupler, reads it process image and publishes
+
+* the new state of a discrete input register (digital input) after a change
+* the new value of an input register (analog input) after a change
+* periodically publishes the current values of all input registers (analog inputs)
+
+using MQTT messages. The topic is built from a configured prefix and the index of the particular registers.
+
+Furthermore it subscribes to MQTT messages related to the coils for the setup and anytime a message is received, it set the particular coils accordingly.
+
+
+### Configuration
+
+Configuration is done using a configuration file
+
+    [modbus]
+    client = 172.16.2.157
+    scanrate = 0.25
+
+    [mqtt]
+    broker = 172.16.2.16
+    digitalOutputTopicPrefix = dt1/coil
+    digitalInputTopicPrefix = dt1/di
+    analogInputEventTopicPrefix = dt1/ai/event
+    analogInputPeriodicTopicPrefix = dt1/ai/periodic
+    analogInputPublishPeriod = 10.0
+    disableAnalogInputEventPublishing = true
+
+### Operation details
+
+While the input and discrete input registers are scanned with the configured scanrate, an action on a coil according to a received message is issued immediately. At the same time the all input registers are scanned.
+
+Using a configuration option it is possible to disable the publishing of analog change event - if only periodic information (like for a thermometer or so) is required.
+
+The MQTT messages related to change events of input or discrete input registers are marked as //retained//.
+
+
+### Usage
+
+The tool is simply started using
+
+    python digitaltwin1.py
+
+On default it searches the configuration file at ``$PWD/config``. This can be changed using the commandline argument ``-f``.
+
+The Python modules ``pymodbus``, ``loguru`` and ``paho-mqtt`` are required.
+
+A docker image with the required dependencies, the tool and a prepared default configuration in a volume is provided at ``registry.hottis.de/wolutator/digitaltwin1``.
+

src/MqttEventPublisher.py

@@ -12,6 +12,7 @@ def mqttEventPublisherStart(config, processImage):
 class MqttEventPublisher(AbstractMqttPublisher):
     def __init__(self, config, processImage):
         super().__init__(config, processImage)
+        self.disableAnalogInputEventPublishing = self.config["disableAnalogInputEventPublishing"].lower() in [ "true", "on" ]
 
     def localLoop(self):
         while True:
@@ -19,6 +20,7 @@ class MqttEventPublisher(AbstractMqttPublisher):
                 self.processImage.wait()
 
                 discreteInputChangeset = self.processImage.getChangedDiscreteInputs()
+                if not self.disableAnalogInputEventPublishing:
                     analogInputChangeset = self.processImage.getChangedAnalogsInputs()
 
             for discreteInputChangeItem in discreteInputChangeset:
@@ -27,8 +29,10 @@ class MqttEventPublisher(AbstractMqttPublisher):
                                        discreteInputChangeItem[1][1],
                                        discreteInputChangeItem[1][0]))
                 self.client.publish("{}/{}".format(self.config["digitalInputTopicPrefix"], str(discreteInputChangeItem[0])),
-                                    str(discreteInputChangeItem[1][0]))
+                                    str(discreteInputChangeItem[1][0]),
+                                    retain=True)
 
+            if not self.disableAnalogInputEventPublishing:
                 for analogInputChangeItem in analogInputChangeset:
                     logger.debug("Analog input {} changed from {} to {}"
                                 .format(analogInputChangeItem[0],
@@ -36,6 +40,7 @@ class MqttEventPublisher(AbstractMqttPublisher):
                                         analogInputChangeItem[1][0]))
                             
                     self.client.publish("{}/{}".format(self.config["analogInputEventTopicPrefix"], str(analogInputChangeItem[0])),
-                                    str(analogInputChangeItem[1][0]))
+                                        str(analogInputChangeItem[1][0]),
+                                        retain=True)