Features combined in an exhibition wall

In the previous months I prepared the PLCnext Technology exhibition wall for the showroom in our Polish Phoenix Contact subsidiary and I would like to show it to the community. 
I made the applications with as many technologies as I was able to, that’s why I used MQTT, OPC UA, Node-RED, Google Home etc.

These four example tasks can be demonstrated:

1. LEDs lighting up after activating the PLC’s input 0
2. Voice message about changing the state of the switches connected to the PLC’s inputs
3. Command “Hey Google, blink” causes the LEDs on the panel to change for a moment to the opposite state and return to their original state
4. Command “Hey Google, check the state” causes that you can hear a summary of the current state of the PLC’s inputs

And here’s how it looks like:

Front side       Back side

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Hardware and software used:

• AXC F 2152
• AXL F DI8/1 DO8/1 1H

and on the PLC’s Linux:

• node.js
• node-red
• node-red-contrib-google-home-notify  – google mini voice messages 
• node-red-contrib-opcua  – OPC-UA communication
• node-red-admin  – Node-RED security
• pm2 – node-red autostart
• Raspberry Pi

The Mosqitto application is running on the Pi, which acts as an MQTT broker.

• Google Home Mini speaker
• Sonoff Wifi Relay

Sonoff relay equipped with AFE firmware Firmware, which adds, among other things, the MQTT communication client.

• Router with Wifi access point and GSM modem

The router creates a Wifi network for all equipment and the GSM modem for Internet connection

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Task 1: LEDs lighting up after activating the PLC’s input 0

Concept

• Switching on the “input 0” switch gives a signal to the PLC’s digital input.
• The program in the FBD language writes the state of the input to the xLight variable, which is shared by the OPC UA server running on the controller.
• Node-RED running on the PLC’s Linux asks the OPC UA server about the state of the variables every second.
  If the xLight variable changes its value, Node-RED sends a MQTT message to the broker (running on Raspberry Pi).
• MQTT client running on Sonoff Wifi Relay reads the MQTT broker state and turns on or turns off the LEDs on the panel.

Staging

see below: Task 1 & 2 combined

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Task 2: Voice message about changing the state of the switches connected to the PLC’s inputs

Concept

• The change of state of one of the three switches gives a signal to the appropriate input of the controller.
• The FBD language program writes the states of inputs to the corresponding variables provided by the OPC UA server.
• Node-Red asks the OPC UA server every second about the state of the variables.
  If a change is detected, it is interpreted by Node-Red flow and google-notify module.
  The corresponding message is sent to the Google Home Mini to be read.

Staging

(Task 1 & 2 combined)

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Task 3: Command “Hey Google, blink” causes the LEDs on the panel to change for a moment to the opposite state and return to their original state

Concept

• The query is interpreted by the IFTTT service and its result is sent to Node-RED.
• Node-RED via OPC UA sends information to the FBD program, which blinks the LEDs in the same way as described at Task 1.

Staging

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Task 4: Command “Hey Google, check the state” causes that you can hear a summary of the current state of the PLC’s inputs

Concept

• The query is interpreted by the IFTTT service and its result is sent to Node-RED.
• Node-RED processes this information in a similar way as described at Task 2.

Staging