Simatic comm problem

[mhans]

Hello everyone ,

I have an engineering station with step7 program.

I can make the modifications from this PC for 7 PLCs.

But now I can not communicate to 3 PLCs now. Also HMI side can not communicate to them. The other 4 PLCs are O.K.

But operating stations can communicate to all PLCs, same network.

When I want to make an online comm. from Step7 for these 3 PLC, the error message appears.

For the same STEP7 program and same PGPC interface, why can I make communication for 4 PLCs and can not make communication for 3 PLCs ? The other operating stations are communicating with all healthly.

Any ideas ?

 

[cardosocea]

How are these interconnected?

 

[mhans]

all PLC s are connected via ethernet connection to PC

PLC connections to IO modules are all Profibus.

 

[Kelkoon]

Comms

Hi,

Can you make a ping from the PC to the failing PLCs?

Are your PG connected in the same place as de Operation Stations?


Best regards,
Kelkoon

 

[mhans]

Hello

Ping is ok for all plcsbut ttl is 30 for these plcs. the others are 60 (ttl)

and the pg is connected to same network as the operating stations.

 

[fredz0003]

What exactly is the error you are getting?
And do you have a topology drawing?

I would try to connect to a switch close to the PLC's you can't reach. It is possible you are losing packets, i.e. lose connection on a switch or even a faulty switch.
Have you checked the switches logs for faults/errors?