I’m working on an MQTT integration using the MQTT_Client_5function block in PLCnext Engineer. The issue is that the client never establishes a connection to my broker, even though basic networking seems fine.
mqttClient(
xEnable := TRUE,
strURI := ‚‘,
strClientID := ‚plcnext_sim_test_12345‘,
xSSL := FALSE,
xServerCertAuth := FALSE,
xCleanSession := TRUE,
xConnected => Connected,
xError => ClientError,
strErrorMsg => ClientErrMsg,
wErrorCode => ErrorCode,
wAddDiagCode => AddDiagCode,
udtMQTTdata := ClientData
);
I see the ErrorCode - 16#0007, ErrorMsg as Disconnected. But there is not request connection I am seeing on the Mosquitto logs inside the docker. Additionally, I see some error logs in Eclr,
18.09.25 19:48:15.279 Eclr ERROR - ClrAllocator::operator new(13975489) failed:
18.09.25 19:48:15.280 Eclr ERROR - usedSize=3984(64 objects), maxUsedBlock=508, unusedMaxSize=1034516
18.09.25 19:48:16.681 Eclr ERROR - ClrAllocator::operator new(13969468) failed:
18.09.25 19:48:16.681 Eclr ERROR - usedSize=3948(64 objects), maxUsedBlock=508, unusedMaxSize=1034552
18.09.25 19:48:16.712 Eclr ERROR - ClrAllocator::operator new(13967461) failed:
18.09.25 19:48:16.712 Eclr ERROR - usedSize=3936(64 objects), maxUsedBlock=508, unusedMaxSize=1034564
18.09.25 19:48:17.484 Eclr ERROR - ClrAllocator::operator new(13963447) failed:
18.09.25 19:48:17.485 Eclr ERROR - usedSize=3912(64 objects), maxUsedBlock=508, unusedMaxSize=1034588
18.09.25 19:48:20.101 Eclr ERROR - ClrAllocator::operator new(13965454) failed:
18.09.25 19:48:20.101 Eclr ERROR - usedSize=3924(64 objects), maxUsedBlock=508, unusedMaxSize=1034576
18.09.25 19:48:20.497 Eclr ERROR - ClrAllocator::operator new(13967461) failed:
18.09.25 19:48:20.497 Eclr ERROR - usedSize=3936(64 objects), maxUsedBlock=508, unusedMaxSize=1034564
Does these cause any issue and what I can summarize is there is no request coming out of the PLC.