How to connect Loadcell transmitter to Plc

[thewalkerist]

First of all i cant seem to know if my plc made a connection to my cb1241 module at all. There are no lights, nothing coming from the module that might tell me its working. How can i know for sure? I connected M to outgoing M of the plc so that it can take energy from there.

Secondly i dont know how to connect my transmitter to my cb1241, Now there is TA, T/RA, T/RB and TB. My transmitter has only two ways, One is called RX/A+ and the other is called TX/B-. How should i make the connection? Please help me.

And after making the connection how can i know if my loadcell transmitter is sending data to my cb1241 or if my cb1241 is sending that data to my plc? There are no lights on in my module so im kinda lost.

 

[goghie]

From your post, which is scarce with details, I can presume that most likely your transmitter is some kind of RS485 Modbus. So you need probably to connect TA and T/RA to A+, and TB and T/RB to B-.
Everything else depends of transmitter specs, and that is speed, parity, etc. plus you need to know exact register map.

 

[thewalkerist]

Okay so i made some improvements. Transmitter works. I can see the weight values from my pc but i cant do anything with my plc, Cant read the values on tia portal and i dont even know if i connected M to the right place(which i connected to the outgoing M of the plc the same way i did my analog output). I connected as you said but i dont see anything. There are no lights, no nothing.

 

[goghie]

Try posting your code, so we can be of help.
Also, did you read the manual Jesper recommended to you?

 

[thewalkerist]

I've read what Jesper posted but to be honest, i did not understand much of it. I just wanted to read the values of my loadcell, It seemed like there was a lot of stuff jumbled together

 

[thewalkerist]

OK so here is what i found while browsing through Tia portal,

"The USS instructions control the operation of drives that support the universal serial interface (USS). With the USS instructions, you can communicate with more than one drive via an RS-485 connection.

To do this, you require a CM 1241 RS-485 communications module or a CB 1241 RS-485 communications board. Up to three CM 1241 RS-485 modules and one CB 1241 RS-485 board can be installed in an S7-1200 CPU."

Instead of PTP_RCV i should be using USS i believe but still have no clue what the differences between them are

 

[JesperMP]

Why start 2 threads for the same topic ?
Both Modbus and USS supports multiple slaves.
The manual says "Modbus", so you should be using Modbus not USS.
As far as I can gather from the other thread, you get the transmitter to do something by sending commands from the PLC. That means that basic comms must be OK. If you can see the data as it comes from the PLC to the transmitter, it might help you debugging the problem.
Contact the manufacturer and get support from them.

 

[thewalkerist]

oh sorry, i couldnt find this topic so i thought that it was deleted. I apologize