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CM1241 send only zeros RS 485

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I have a Siemens S7-1200 and CM1241 module. I use them for my pressure sensor.

But I had to test the sensor on Mitsubishi PLC. Then I went back to Siemens (which I hadn't turned on for a while and didn't do anything with it). Now Siemens doesn't interact with sensor.

Then I connected PLC to a PC via USB-RS485 adapter, it sends " 00 " every second. I used to work with this adapter and both PLCs and saw the correct commands.

I also tried two different CM1241 modules.

Can you help me determine what the problem might be? 

Converter, sensor and all cables are operable.

Hardware config: 9.6 kbps; Even parity; 8 bits; 1 stop bit.

MB_COMM_LOAD: baud - 9600; parity - 2; Correct MB_Master_DB and CM-1241 port

MB_MASTER: mode - 0; Data_addr - 30003; Data_len - 2; Data_ptr - my DWORD tag

P.S.: I can't upload screens. Server return error...

Edited by nikitost

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It seems that you mixed S7-200 with S7-1200.

S7-1200 can  be accessed by Ethernet interface, not by RS485 ( you wrote RS458...).

Try to explain again.

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dekor thank you for answer!

My PC-PLC connection is ok (via Ethernet) but I'm talking about a PLC-Sensor connection.

I've already set up the connection between the PLC and the Sensor before. It looks like:

| Siemens S7-1200 + CM1241 | <--- 2wire RS-485 ---> | Sensor |

I had a break from working with this PLC. Now that I've returned to it. And now it doesn't send the necessary commands...

Previously, PLC could send command "01 04 0002 0002 D00B". And now only "00" every second.

Could it be a malfunction of the PLC itself? Is there a way to check this myself?

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Ok... it was a cable...

BUT! First cable works only with Mitsubishi PLC

And second works with both :shrug:

The issue has been resolved :-)

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