Slave PLC problem

Hi,

I was wondering if any one could help in understanding how to configure and communicate between master and an intelligent slave, both PLCs are CPU 314 C-2 DP.

At the moment I have configured the master PLC on the PROFIBUS DP network and it works (thanks to help from this forum). I have used the Step 7 help menu (“Configuring the CPU 31x-2 DP as a slave”) to set up the other CPU 314 C-2 DP as an intelligent slave. I can see this PLC (slave) on the network as a passive device at address 5 in diagnostics of the CP 5613 PCI and have downloaded the master station to the master PLC and the slave station to the slave PLC separately, everything seems ok. I wrote a simple program to switch on an input on the master to turn on an output on the slave but it does not work. Am I missing something?

Thanks.

I don't know what is in the help files for configuring a 31x-2 DP as a slave, but have a look at this site (click here) module D6 might be of some help to you, even though it deals with 315's

Paul

Thanks Paul, thats great.

Thanks for the link to the training material Paul.

John

I think it was Ron (rsdoran) who first posted this link, it has been posted many times since then, so thanks should go to Ron.

Paul

32 bits of data be converted to 16 bits of data

Hi everybody

I am using express from microsol product.I have a problem at the master which only excepts 15 bits of Analog data (1 bit reserved for signed bit) but the slave can only send 32 bits of analog data, so I have to use the above product to perform limited PLC programs. However, i am a newbie to PLC. Someone suggested to convert the 32 bits to 16 or 15 bits. Could anyone advice me on how to write a simple PLC to the above mentioned problem. If it is in other PLC lauguage,it's ok for me because I still can have a general idea of how to solve this problem. Thank you very much.

Hi axeman.

You should have started a new thread in stead of posting in this one.

I assume that you are talking about Profibus master and slaves.
What type is the master ?
What type is the slave ?
Did you import a GSD file from the slave into the configuration of the master ?
For Profibus DP, you normally "only" have to insert the slave into the masters configuration, and then normally everything should be taken care of.
(There is an issue with Byte swapping, but that is a different problem).
So I dont see where the problem with 32 or 16/15 bits is coming from.

Hi JesperMp

Thanks for your reply. I think you are right, the type of master is Power CC, the type of slaves is Xcell rtu and some types of IED(not sure which type) connected to it through modbus slaves. The IED's can only send 32 bits of data to the master and we want this 32 bits of data to be converted to 16 bits of data because power cc is already configured to accept only 16 bits of data. hmm...i just wondering how the 32 bits be converted to 16 bits in PLC concept. By the way, i know we can use function blocks to do the converting right ?

Dear axeman.

I have absolutely no knowledge of any of the problems or equipment you have.

To sum it up:
You have a modbus master ("Power CC" - never heard of it).
You have several modbus slaves ("Xcell" and "IED" - never heard of them either).
I hope that someone that knows about these sees your post, but the chances are slim as this thread is about Profibus and not Modbus.
I suggest you start all over with a new thread and then provide as much information up front.