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MQTT and blob massages [message #1839510]

Tue, 23 March 2021 01:59

Eclipse User

I'm confused by choosing right type to receive binary message by SUBSCRIBE_1 function block and MQTT layer. What is the most appropriate type for output of SUBSCRIBE_1 function block? I've tryed STRING.
Forte work fine. But 4diac monitor hang if I try to watch SUBSCRIBE_1 or it output by STRING2STRING (and close debug connection to forte). I check forte code. As I understand, the unprintable characters in message are the problem (they corrupt the structure of debug xml packet).
Probably I should use another type instead STRING?

Re: MQTT and blob massages [message #1839579 is a reply to message #1839510]

Wed, 24 March 2021 03:07

Eclipse User

I fear 4diac FORTE is currently not able to handle binary representations in monitoring well. Maybe the best solution would be an array of bytes. However as IEC only allows fixed sized arrays you need to find another way to store the length of the array. One option could be that you keep the string for the Subscribe_1 and build yourself an FB converting it to a BYTE array with a second output of the fill size of the array. This you should be able to watch. Or you could try the out console FB. printing the receveived data to the console if your device permits.

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