Modbus TCP Scadapack 474 and S7-1200

[rusaarce]

Hello I am new programming the scadapack 474, these last few days I have tried to establish modbus communication through the scadpack and the PLC 1200, but for some reason I have not been able to send data from the scadapack to the PLC, does anyone know what to do in this case?

[Joel_Weder · Accepted solution]

Hello Rusaarce,

I won't be able to provide assistance with the S7-1200 PLC, as I don't have any knowledge of that Siemens device. All I can say is that its comm parameters will need to be set to work properly with the SCADAPack 474. E.g. each needs its own (unique) Modbus station number and IP address. 

You didn't mention if you're trying Ethernet or serial comms. If Ethernet, make sure both devices are in the same subnet and have different addresses. If serial, all the usual parameters must match - baud rate, parity, stop bits etc. And serial cables can be challenging. SCADAPacks work well with just a 3-wire cable. (swap RxD and TxD as both devices are DTE)

The SCADAPack 474 uses the Modbus Scanner capabilities of RemoteConnect to poll other Modbus devices. (to read or write data) These videos discuss the Modbus Scanner in some detail:

https://www.youtube.com/watch?v=pqN0oObZGuo

https://www.youtube.com/watch?v=c8NMGqhqOZI