CP-342-5 communication

Basically what I am looking to do is move some basic digital Inputs and outputs between 3 PLCs. The system is already setup and has

Station 1. - CPU-317, 342-5, 342-5, I/O modules
Station 2. - CPU-314, 342-5, I/O modules
Station 3. - CPU-315, 342-5, I/O modules

Stations are interconnected with 342-5 modules and by Fiber using OLMs

Communication profibus no DP

Station 1 has database tables Station 2 and 3 both have same setup as far as tables go.

Send DB100
Receive DB101

They currently communicate and everything working fine right now...

What I want to add to what is existing is take say on Station 3 take I5.2 and have that output on Station 2 as Q7.2

I think what needs to happen is on Station 3 I add to FC to set
DB92.DBX14.5 = I5.2 (14.5=next unused value)

Then on Station 1 in FC set DB100.DBX14.4(next unused value) = DB93.DBX??.? (here is where I run into problem explain more below)

Then on Station 2 in FC set Q7.2 = DB101.DBX14.2 (next unused value)


My problem is I can't figure out how or where the program takes the DB table and sends/receives the data. I tried to follow some data from the existing code but it goes I5.0 -- DB100.DBX14.2 --- DB92.DBX6.2 -- then to logic...

It would make sense to me if DB100 was sent from Station 3 and on Station 1 that table was repeated in DB92 So DB100.4.1 was the same data as DB92.4.1 but that does seem to be the case. I can't even find where it says.. to load the incoming data in DB92 or send from DB100 etc... Maybe if I can find that I can see the offset or where it does assignments etc. Is this something I can only see on the online code? (Working with just the offline code right now)


Your help figuring this out would be much appreciated.

Ralph

I can't even find where it says.. to load the incoming data in DB92 or send from DB100 etc...

Click to expand...

by that, I take that you are not the original programmer.

The way you describe it, it sounds as if the data is tranferred via a configured NetPro connection and Send/Receive (because of the "no DP"). Look for the blocks AG_SEND and AG_RECV.
(the words "send" and "receive" are sometimes also used when the datatransfer is via Profibus master-slave, because the blocks DP_SEND and DP_RECV must be used in that case).
The source and destination configuration of the AG_SEND and AG_RECV blocks will reveal why there is an offset so that a bit is in byte 14 in one DB and in byte 6 in the other DB.

Apart from that, I think you should not touch the setup of the datatransfer. In stead, just map out at what adresses the inputs in one CPU arrive as data in the other CPU, and vice-versa. Then you will know what to do.

No I am not the original programmer. Problem is there isn't any send / receive blocks unless it is in a protected system call.

Will try just to use the empty space and see how it goes. Would really like to know where the info is for the data transfer though.

Is there somewhere that you could point me to that has examples of the dp_send receive blocks so I make sure I am looking for the right thing?

thanks for the help

Ralph

AG_SEND and AG_RECV are protected blocks, but they should still appear in the cross reference.
If you look at the blocks view in Simatic Manager, you can try to look for AG_SEND and AG_RECV, and for protected blocks (there is a small padlock symbol next to the block icon).