M172 Communication module option

[StevenCho]

Hi all,

Is there no option to add Modbus master on M172?

When I add RS485 Plug-in and set it to master, the following error is occured.

"ERROR: (BuildCfg_RS485) Too many Modbus RTU masters: only 1 allowed"

It seems M172 doesn't support 2 RTU Master, Is it right?

Then is TM172SIP could be alternative?

Thanks in advance.

Regards, Steven Cho 

[FedericoM · Accepted solution]

Hello,

sorry for very late answer, I haven't seen this post before.

M172 supports 1 modbus master over RS485.

An alternative solution could be:

2 TM172 connected through Modbus/TCP, each of them master of a RS485 network.

TM172 Secure Inteface Gateway could manage 1 RS485 and be master of the TM172 master of a 2nd network.

[Bastian_Schmitz]

If you need two seperated Modbus RTU Master it could also be a solution to combine your PLC with an HMI like HMIST6. In that case you have Modbus RTU and TCP on the HMI. You could use TCP to communicate to the PLC and the RTU on the HMI as second master.

[StevenCho]

By the way,

Is there any reference document regarding Combining Two TM172 through ESME-HVAC Installer?

I heard the concept and want to try it.

(It seems that TM172P works as Expansion module which is I/O and Communication integrated)

But have no idea about Installer program.