24_7 Mosquitto setup

To be able to publish using MQTT in Codesys some prerequisite changes and settings needs to be done, this is a step by step guide on how to publish with MQTT in Codesys.

First step is to change IPv4 settings on the Ethernet port. This is done by going into (Settings → Network & internet → Ethernet) and under the tab IP assigment press edit then change from automatic to manual and turn on IPv4, and change to the settings show in this image:

The PLC which is currently in use has the IP: 158.38.140.53 and the IP for the Ethernet port is set to the same but +/- 1 to the last digit. And change the Subnet mask to 255.255.255.0.

Next step is to change the cloud connectivity settings for the PLC, this is done by writing the PLC's IP into the search bar of a web browser. The settings to change are found under:

(Configuration → Cloud Conectivity → Connection 1 or 2) here we change the settings to match our IPv4. We start by first changing the "Cloud platform" to MQTT AnyCloud, the "Hostname" will be the same as the IPv4 and thus for this example 158.38.140.54, the port will be 1883 which is for unencrypted MQTT connections, and lastly "Data Protocol" will be changed to Native MQTT. The settings should look like this:

Assuming everything is running localy, the last change is to add a rule to the PC's firewall, this is done by entering (Control panel → System and Security → Windows Defender Firewall → Advanced settings → Innbound Rules → New Rule...)

The new rule should be of type Port and TCP 1883.

Publishing from Codesys

To publish from Codesys the libraries wagoAppCloud and wagoSysPlainMem are used, these are added by using the "Libary Manager" in Codesys.

FUNCTION_BLOCK MQTTPublisher
VAR_INPUT
    topic : STRING(255);
    xtrigger : BOOL;
    message : STRING := 'Hello, World';
END_VAR
VAR
    mqttPub : wagoappcloud.FbPublishMQTT_2(econnection := econnectionid.Connection1);
    dwSize : DWORD;
    aData : ARRAY[0..100] OF BYTE;
    xRetain : BOOL := FALSE;
    xError : BOOL := FALSE;
    xBusy : BOOL := FALSE;
    eQualityOfService : eQualityOfService;

END_VAR

_____________________________________________________________

wagosysplainmem.MemCopy(pDest:=ADR(aData),pSource:=ADR(message),udiSize:=TO_WORD(len(message))); 
mqttPub(sTopic:=topic,eQualityOfService:=eQualityOfService,xRetain:=xRetain,dwSize:=TO_WORD(len(message)),aData:=aData,xTrigger:=xtrigger,xBusy=>xBusy,xError=>xError);

This is a simple code to publish "Hello, World!"