GE Fanuc COMM_REQ

Hi all, I need to know more abut the COMM_REQ function in proficy ME.
When doing a read request, can i trigger the read function on every 1st scan? See file attached. When writing, do i have to wait for the read to be complete, or can i trigger them both on the 1st scan?

If the port you are Reading from is ready on the first scan you will be able to attempt a Read then. On the Write 'it depends'. If the Write is the same port but a different channel, yes else you will need to wait for the Read to return a 1 to the 'Status Register'.
Maybe you could include the 'Rung Comment' that includes details of each register in the COMMREQ.

ok cool, so after a successful read/write the status register returns a 1?

It looks like you copied the example from GFK-1541, page 3-44 with modifications to the specified address in your local PLC. The command sets up a read channel for SRTP communications using an ethernet interface module in rack 0, slot 6.

As configured, when the PLC first starts running its program you're setting up the channel to read 8 words of %R memory starting at %R50 in a PLC with IP address 10.0.0.1. You're going to store that data in %R330 - %R337 in this PLC. You're going to read the data every seven seconds, but you're going to stop after ten read transactions.

I'm guessing you really want to set up for continuous reading, not stopping after ten reads, so you probably want to change the value at IN2 of the second BLKMOV instruction to zero.

Since the VersaMax Micro doesn't have ethernet capability, you'll be using an ethernet-to-serial converter at that end. 500 milliseconds might not be a long enough timeout (IN5 of the second BLKMOV) since the converter needs to get the request from the host PLC, convert it to a serial (SNP) command string, transmit it to the VersaMax Micro, get the response, convert it to SRTP and pass it back to the host PLC.

mot said:

ok cool, so after a successful read/write the status register returns a 1?

Click to expand...

That is correct, it is also the reason that the example shows MOV_WORD "0" into the 'Status Register' just before the COMMREQ. Also be aware that anything >1 is an error.

ok thank you, the versamax has an ethernet option module configured as rtu slave, so i should be able to go straight with ethernet.

With your COMMREQ talking SRTP you will need to change the VersaMax Micro to SNP slave, also be sure to get the latest version firmware on your VM Micro, both for the PLC and the Ethernet module, this will allow you to set the serial side of the Serial-to-Ethernet port to 175,000 baud and give you the best throughput.
Also do not forget that this is a Serial-to-Ethernet adapter not a full 10/100 Ethernet port.

thanks again, ive arranged with our GE Fanuc suppliers to borrow the two plc's so that I can test my logic before I get to site. I think I should be able to get comms

Cheers
M