Hi, 

First of all, thank you for answer!

I have modified the program because this behaviour looks very strange for me. I storage the status and see that I have a #80C8 status error. According to documentation: "The slave does not respond within the set time" and the remedy is to "Check the data transmission rate, parity and wiring of the slave". 

As I had tested with software I know that the transmission rate and the parity is ok. I have checked the wires and they are in perfect condition. 

Is there any other cause that can be the problem of this?

Thank you very much in advanced!

Thank you so much! 

It was a problem of the wire connection. I swapped in one side and now everything works fine. 

I tested two different sensors and it works properly with both of them. Now I have a problem connecting both of them at the same time. 

I made a Function Block for each sensor. This way I can activate and deactivate individually. However I received a new error in the communication master block #8200.

Do you know what the problem could be? 

Thank you so much in advanced! 

Duris_I

Hello,

good news finally.

Now I have a problem connecting both of them at the same time.

This isn't possible. You can poll data only from one Slave at time then set REQ to false, change parameters or enable second block REQ to start next. Important rule - poll data only from one device at time.

 Hi! 

Yes, I know, thats why I designed the main block as the attached image. I am reading only one sensor (block) at time. However I am receiving a 8200 code that means: "Port is busy processing a send request". This shouldn't be a problem as I am only using one block at time.

What could be the problem? 

Thank you in advanced!

MB_COMM_LOAD should only be used once per port. It should not be called for every slave.

Working on a timed based trigger is a chances for problems. The REQ pin of the master block should see the transition from ON to OFF before the next master block get permission to switch. There are application examples on this support site supplied by Siemens. Also the forum has some examples, but harder to find.