Codesys not connecting to mqtt server

[sanderobdeijn]

I have a Wago PFC100 and I have a mqtt server running in my local network without authentication. I have tried the testMQTT(client:={mqttserver:1883} test function but the plc doesn't seem to connect to the mqtt server. When I look at MQTTClient > MQTT_Control > sResultIp the value is empty. When I look at #3 I think this value should be set. If this doesn't works it suggest a dns issue?

[stefandreyer]

Hi Sander,

does you URL_DATA looks like this?

Do you realy write testMQTT(client:={mqttserver:1883} ?

should look like: testMQTT(client:='mqttserver:1883')

BR Stefan

[sanderobdeijn]

what i wrote was: testMQTT(client:='DESKTOP-2NKGLRM:1883'); And my url data looks like this. And I don't see a connected client to my mqtt server. Connecting by Ip doesn't work also.

[stefandreyer]

Hi Sander,

with a static IP it have to look like:

With static IP I don't use DNS, this have to work.

You may look in ErrorHistory in HANDL_MQTT, maybe you have a problem with dynamic memory.

If this, I don't stat conecting or spliting connection string.

BR Stefan

[stefandreyer]

Hi Sander,

with a static IP it have to look like:

With static IP I don't use DNS, this have to work.

You may look in ErrorHistory in HANDL_MQTT, maybe you have a problem with dynamic memory.

If this, I don't stat conecting or spliting connection string.

BR Stefan

[sanderobdeijn]

Hi Stefan I have set a static ip in the web based management page. This doesn't fix it.

I have looked at the error history. And you called it. It seems to be a dynamic memory issue. What does this mean. Is this a hardware issue or a configuration issue?

[primsam]

Hi Stefan I have set a static ip in the web based management page. This doesn't fix it.

I have looked at the error history. And you called it. It seems to be a dynamic memory issue. What does this mean. Is this a hardware issue or a configuration issue?

Hi , That ist a configuration issue . You need to increase the dynamic memory

Right click on the application

• properties
• Dynamic memory settings
• increase maximum size of memory

[sanderobdeijn]

How much memory do I need? Do you know? And can you have more dynamic memory than ram or are they linked?

For others I have increased my memory to 150 mb or 153600 bytes and now it works. @stefandreyer you should put this in the setup instructions maybe.

[stefandreyer]

Hi Sander,

here you see your usage of dynamic memory in bytes:

If you use more subscriptions and more instances of callback FBs this will grow.

and yes, it could be usefull to set up some setup instructions ;)

BR Stefan

[sanderobdeijn]

this usage is in bytes or mb? 100 mb wasn't enough for the GreatExampleOfAdvantages project. my plc only has 256 mb ram does this also limit the dynamic memory?

[primsam]

This is displayed in Bytes i think. At least when i limit Dynamic memory at 20000 Bytes it run without Problems

[stefandreyer]

Hi,

yes these are Bytes. I testet the GreatExampleOfAdvanteges with 20000Bytes(20kByte).

At most I setup my Raspi with 2000000 Bytes and got enough left.

@sanderobdeijn yes your physical memory limits the dynamic memory. But my lib takes only veeery few of it. I think with 1000000(1MByte) you can make almoste everythink with my lib on your plc... 100MBytes(100000000) are more then enough for this example.

BR Stefan

[sanderobdeijn]

yeah my bad I forgot about Kbytes. I have used 153600 bytes or 150 kBytes. It has been long since I had to calculate in bytes.