FB_RS485_DUCO_DUCOBOX_MQTT

General

Used to process Modbus RTU data through RS485 to human understandable values and publish data updates through MQTT if desired. Allows finegrained local control on your DucoBox.

🚨 In order to leverage this modbus integration a communication print (partnumber 0000-4251) is required on the DucoBox.

DUCO DUCOBOX Focus data:

Productlink
Modbus registers

Block diagram

METHOD(S)

InitMQTT: enables MQTT events on the FB, an overview of the parameters:
- MQTTPublishPrefix: datatype POINTER TO STRING, pointer to the MQTT publish prefix that should be used for publishing any messages/events for this FB. Suffix is automatically set to FB name.
- pMqttPublishQueue: datatype POINTER TO FB_MqttPublishQueue, pointer to the MQTT queue to publish messages.
- pMqttCallbackCollector: datatype _POINTER TO MQTT.CallbackCollector, pointer to the MQTT callback collector to receive subscribe messages.
InitRS485: configures the Modbus RTU device address and the execution/polling interval for the multiple modbus read commands.
RequestBusTime: method implemented by each RS485 device function block. More information in the RS485Device interface docs.
GetRtuQuery: method implemented by each RS485 device function block. More information in the RS485Device interface docs.
ProcessDataArray: method implemented by each RS485 device function block. More information in the RS485Device interface docs.

MQTT publish behavior

Requires method call InitMQTT to enable MQTT capabilities.

Event	Description	MQTT payload	QoS	Retain flag	Published on startup
register is polled	a modbus register is polled	int value	2	`FALSE`	no

MQTT publish topic is a concatenation of the publish prefix and the function block name, the node numer and a register number. For example:

Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT/1/read/0

Depending on the type of the node the published register value represents a certain parameter value.

MQTT subscribe behavior

Requires method call InitMQTT to enable MQTT capabilities. Commands are executed by the FB if the topic MQTTSubscribeTopic matches the MQTT topic and the payload exists in the table below.

Command	Description	expected payload	Additional notes
write holding	Writes an integer value to a specific write register.	`INT`	Only integer values are processed further.

MQTT subscription topic is a concatenation of the subscribe prefix variable, function block name, node number and register number. For example, topic Devices/PLC/House/In/RS485/FB_RS485_DUCO_DUCOBOX_MQTT/1/write/0 with payload 30 will set the 'Target value (%)' parameter for node 1 (which in this case represents the entire system). Go through the DUCO modbus register documentation linked above for a deeper understanding.

Upon a successful write operation the received payload will be published on the 'Out' topic. Continuing with the example above this will result in a payload 30 to be published on topic Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT/1/write/0.

Code example

variables initiation:

MQTTPubRS485Prefix                :STRING(100) := 'Devices/PLC/House/Out/RS485/';
FB_RS485_DUCO_DUCOBOX_MQTT_001    :FB_RS485_DUCO_DUCOBOX_MQTT;

Init RS485 method call (called once during startup):

FB_RS485_DUCO_DUCOBOX_MQTT_001.InitRS485(
	DataPollingInterval := T#20S,       (* Polling interval *)		
	DeviceAddress := 1                  (* Device address of the modbus device *)			
);

Init MQTT method call (called once during startup):

FB_RS485_DUCO_DUCOBOX_MQTT_001.InitMqtt(
	MQTTPublishPrefix:= ADR(MqttRS485Prefix),                       (* pointer to string prefix for the mqtt publish topic *)
	pMqttPublishQueue := ADR(MqttVariables.fbMqttPublishQueue)      (* pointer to MqttPublishQueue to send a new Mqtt event *)
);

The MQTT publish topic in this code example will be Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001 (MQTTPubSwitchPrefix variable + function block name).

Registering device to a buscontroller (called once during startup):

RS485BusController.RegisterDevice(device := FB_RS485_DUCO_DUCOBOX_MQTT_001);

Home Assistant YAML

To integrate with Home Assistant use the YAML code below in your MQTT sensors config.

Main node:

mqtt:
  sensor:
  - name: "Ventilation Status"
    object_id: "ventilation_1_1"
    state_topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/1/read/1"
    value_template: >-
          {% set val = value | float(0) %}
          {% if val == 0 %} Auto
          {% elif val == 1 %} 10 minutes high
          {% elif val == 2 %} 20 minutes high
          {% elif val == 3 %} 30 minutes high
          {% elif val == 4 %} Manual low
          {% elif val == 5 %} Manual medium
          {% elif val == 6 %} Manual high
          {% elif val == 7 %} Unoccupied
          {% elif val == 99 %} Error
          {% else %} Unknown
          {% endif %}
    icon: "mdi:state-machine"
    qos: 2
    availability:
      - topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/availability"
      - topic: "Devices/PLC/House/availability"
    availability_mode : "all"
    payload_available: "online"
    payload_not_available: "offline"
  - name: "Ventilation Pos"
    object_id: "Ventilation_1_2"
    state_topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/1/read/2"
    unit_of_measurement: "%"
    icon: "mdi:valve"
    qos: 2
    availability:
      - topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/availability"
      - topic: "Devices/PLC/House/availability"
    availability_mode : "all"
    payload_available: "online"
    payload_not_available: "offline"
  - name: "Ventilation Power"
    object_id: "ventilation_1_3"
    state_topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/1/read/3"
    unit_of_measurement: "W"
    device_class: "power"
    state_class: "measurement"
    qos: 2
    availability:
      - topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/availability"
      - topic: "Devices/PLC/House/availability"
    availability_mode : "all"
    payload_available: "online"
    payload_not_available: "offline"

Additional nodes (for example valves):

mqtt:
  sensor:
  - name: "Ventilation Node 2 Status"
    object_id: "ventilation_2_1"
    state_topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/2/read/1"
    value_template: >-
          {% set val = value | float(0) %}
          {% if val == 0 %} Auto
          {% elif val == 1 %} 10 minutes high
          {% elif val == 2 %} 20 minutes high
          {% elif val == 3 %} 30 minutes high
          {% elif val == 4 %} Manual low
          {% elif val == 5 %} Manual medium
          {% elif val == 6 %} Manual high
          {% elif val == 7 %} Unoccupied
          {% elif val == 99 %} Error
          {% else %} Unknown
          {% endif %}
    icon: "mdi:state-machine"
    qos: 2
    availability:
      - topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/availability"
      - topic: "Devices/PLC/House/availability"
    availability_mode : "all"
    payload_available: "online"
    payload_not_available: "offline"
  - name: "Ventilation Node 2 Pos"
    object_id: "ventilation_2_2"
    state_topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/2/read/2"
    unit_of_measurement: "%"
    icon: "mdi:valve"
    qos: 2
    availability:
      - topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/availability"
      - topic: "Devices/PLC/House/availability"
    availability_mode : "all"
    payload_available: "online"
    payload_not_available: "offline"
  - name: "Ventilation Node 2 Temp"
    object_id: "ventilation_2_3"
    state_topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/2/read/3"
    value_template: "{{ value | multiply(0.10) | round(2) }}" 
    unit_of_measurement: "°C"
    device_class: "temperature"
    state_class: "measurement"
    qos: 2
    availability:
      - topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/availability"
      - topic: "Devices/PLC/House/availability"
    availability_mode : "all"
    payload_available: "online"
    payload_not_available: "offline"
  - name: "Ventilation Node 2 CO2"
    object_id: "Ventilation_2_4"
    state_topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/2/read/4"
    unit_of_measurement: "µg/m³"
    device_class: "PM25"
    state_class: "measurement"
    qos: 2
    availability:
      - topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/availability"
      - topic: "Devices/PLC/House/availability"
    availability_mode : "all"
    payload_available: "online"
    payload_not_available: "offline"

Writing registers (for example action on valves):

mqtt:
  button:
  - object_id: "ventilation_2_write_9_15high"
	name: "Ventilation Kitchen 15 min high"
	command_topic: "Devices/PLC/House/In/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/2/write/9"
	payload_press: "4"
	availability:
	- topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/availability"
	- topic: "Devices/PLC/House/availability"
	availability_mode : "all"
	payload_available: "online"
	payload_not_available: "offline"
	entity_category: "config"
  - object_id: "ventilation_2_write_9_Auto"
	name: "Ventilation Kitchen auto"
	command_topic: "Devices/PLC/House/In/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/2/write/9"
	payload_press: "5"
	availability:
	- topic: "Devices/PLC/House/Out/RS485/FB_RS485_DUCO_DUCOBOX_MQTT_001/availability"
	- topic: "Devices/PLC/House/availability"
	availability_mode : "all"
	payload_available: "online"
	payload_not_available: "offline"
	entity_category: "config"

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FB_RS485_DUCO_DUCOBOX_MQTT.md

FB_RS485_DUCO_DUCOBOX_MQTT.md

FB_RS485_DUCO_DUCOBOX_MQTT

General

Block diagram

MQTT publish behavior

MQTT subscribe behavior

Code example

Home Assistant YAML

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FB_RS485_DUCO_DUCOBOX_MQTT.md

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FB_RS485_DUCO_DUCOBOX_MQTT.md

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FB_RS485_DUCO_DUCOBOX_MQTT

General

Block diagram

MQTT publish behavior

MQTT subscribe behavior

Code example

Home Assistant YAML