PLC TM171 | Cannot connect to target

[Maiza]

• I've already tried using speeds of 9600 and 19200 with the E, 8, 1 and N, 8, 1 configurations. The same converter port configuration for these speeds has also been checked. I have 4 electrical panels out of service due to this problem and I'd like to find a solution without having to replace the PLC, as this is unacceptable. 

It looks like the communication board is burning out, it's very strange.

 

[M_Cervati]

Hi, 

how is the connection mode? Using ADMI tool or port RS-485?

If you are using ADMI and you are using port on board RS-485 like master, you have to disable the master because the hardware port is the same.

If you are using ADMI or RS-4885 on board check the communication BIOS parameter CF30, CF31, CF32, using the BIOS menu navigation on keyboard and display.

If you are using LAN port in modbus check the communication BIOS parameter CF35, CF36, CF37,using the BIOS menu navigation on keyboard and display.

Best regards

Marco Cervati

[Maiza]

Good morning, how are you? I managed to solve it yesterday, but I would like a technical explanation of how it works from you at Schneider (instinctively, it seems that EwDMI is based on the Modbus protocol, consequently, we have to transfer the programming according to this protocol). Well, the first few times we were only able to transfer the programming once, then we couldn't keep connecting the PLC to the computer and staying online. Since I needed to communicate with these PLCs on a single HMI, I set the Modbus configurations via the PLC display (CF30, CF31 and CF32), since we could no longer stay online through the programming. And yesterday, then, I went to Set Up Communication and configured the protocol (19200, Even, 8 and 1) in EwDMI and consequently its PLC address (Address), which I had set via the display and...it worked! I did the same test on 4 panels and that really is the solution. Now I would like a technical explanation at the EwDMI level, how it works and if this is indeed the procedure I just described.

[FedericoM · Accepted solution]

Hello,

the RS485 port and TTL port of TM171O are the same serial, they can't be used at the same time.

Every time you change the serial settings of TM171O a reboot is needed.

You have only to configure the connection settings in order to be aligned to CF30,31,32.

If the controller is configured as modbus master, you can connect only at boot (modbus master will be disabled)