Why didn't X_GET work?

[leem2209]

I have 3 PLC's as part of a group of machines.

A "Transport" section to "Machine 1" and "Machine 2".

Each has a CPU315-2 DP.

I want to transfer a 70 byte data block from "Machine 1" to "Transport" and same for "Machine 2".

There are DPP couplers to give handshake signals but they are set up for only 11 bytes Input and 11 bytes Output. Expanding this will affect the I/O addressing of other remote I/O units on the profibus.

All the PLC's are connected by MPI. There is one common connection point on the front of the "Transport" panel and I can connect with the PG to each of the PLC's through this.

MPI addresses are "MC1plc=2" "MC1touchscreen=1" "MC2plc=7" "MC2touchscreen=9" "TransPlc=3" "TransportCP=4" "TransportTouchscreen=5"

So I thought I'd be able to set up X_GET twice in the "Transport" PLC to retrieve the required data from "Machine1" and "Machine2"

Set up as follows:

REQ = M2.5 (1 sec clock)
CONT = M0.1 (Always Off)
DEST_ID = W#16#2 (For Machine 1, MPI 4) W#16#7 (For Machine 2, MPI 7)
VAR_ADDR = P#DB23.DBX0.0 Byte 70

RET_VAL = #mc1_retval
BUSY = #mc1_busy
RD = P#DB100.DBX30.0 Byte 70 (MC1) P#DB100.DBX100.0 Byte 70 (MC2)

My RET_VAL is showing 28674/28672

But data is not transferred into DB100 in my "Transport" PLC. I've tried writing each DB to separate datablocks too but same result.

I was hoping to try X_PUT in "Machine1" and "Machine2" but ran out of time.

I am also thinking of trying X_SEND and X_RCV but if X_GET doesn't work then I assume X_SEND, X_RCV and X_PUT won't work either.

Any suggestions?

 

[leem2209]

I've seen a couple of things about MPI comms...

One item showed both PLC's in a single project and comms working using X_Send

One post said that the PLC's do not need to be in the same project.

I have 3 separate projects. Do I need them all in a single project? Or do I need to define the connections (Insert new connection under NetPro?)?

 

[leem2209]

UPDATE!

Now working. All it required was a CPU re-start.

I found an example of X_GET and X_PUT use on Siemens website and it mentioned putting the CPU into stop before downloading so on re-start it loads SFC67/68 properly.