MQTT client - AXC F 2152

PLCnext Technology & PLCnext Controls
1

I am currently trying to establish an MQTT connection to PLCnext. The values ​​of user-specific process data should be sent as a pure string (no JSON) to a broker and read from there. The following working environment is used:
EDULINE starter kit with AXC F 2152, FW: 2021.05
PLCnext Engineer 2021.3
MQTT_Client_Library_3
As a programming language I use ST and optionally FBD.
Hiveqm’s public broker is used as the MQTT broker, and Hiveqm’s public MQTT client (web client) for testing.

Results:
Connection to MQTT broker: OK
Method Publish: OK; the process data is fast transferred to the broker.
Method Subscriber: OK
Method StartConsuming: OK
Method TryConsumeMessage: No reaction, process data are not received (anyPayload remains empty), no MQTT errors in the output.log file

The process data written by the Hiveqm MQTT client is not received by the TryConsumMessage method, although there is a working connection to the broker. A test with another MQTT client showed that the broker actually sent the written process data. Attached is my FBD program.

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Maybe someone would have recommendations for troubleshooting or further testing.
Many thanks for the efforts.
Reinhard

2

I’d like to suggest that the firmware in the device be upgraded to at least the latest LTS version (2022.0.4), and that the MQTT_Client function block from the IIoT_Library is used. The MQTT_Client_Library is no longer in the PLCnext Store, so the documentation (and support) for that library is no longer publicly available.

3

Thank you for your recommendations. I have now updated the FW to 2022.0.4 and also work with PLCnext Engineer 2022.6 and the IIOT_Library_3 from the PLCnext store.
Unfortunately, Publish no longer works either, since a connection can no longer be established:
The creation of the MQTT client instant is OK, but after triggering an xRequest in the “Connect” method, xBusy remains TRUE for approx. 60 s and then the error message 16#0006 and the message “TimeOut” are output in the udtdiag.
Perhaps you have one more hint.

Thank you very much
Reinhard

4

The connection to port 1883 of the Mosquitto test broker should work ok. If not, can you show your FB call and your call to the Connect method of that FB?