Ge fanuc plc communication

HELLO ALL !!!

I want to control three VersaMAx IC200UAL006 PLC on Modbus communication. One is the master PLC and the other two is the Slave PLC. I want to read and write the Holding Register , Discrete Inputs,outputs of slave PLC.

Master PLC Port#2 Rs-485 , Station address#1 , Baud Rate 9600
Slave PLC Port#2 Rs-485 , Station address#1 , Baud Rate 9600
Slave PLC Port#2 Rs-485 , Station address#2 , Baud Rate 9600

I've Programmed Master PLC according to the manual attached with it.
For testing i've check master PLC communication By using MODBUS POLL Software and is working great.

Now what I want to know is ...

1) Whether I've also use the COMMREQ instruction in the Slave PLC's or Not ??

2) When I connected the Slave PLC along with master it doesn't show me any data change.

According the Program ... With reference to the manual attached

Page #33 , R0125 is the slave addresses and R0831 are the master addresses for slave#1.

Page #33 , R0002 is the slave addresses and R0731 are the master addresses for slave#2.

3) With Reference to page#4 , I'm using the cable connection given on Page#4. But still it is not working.

PLEASE let me know where i'm doing mistake.

Manual Name: gfk2220a.pdf

Regards,
Unus Iqbal

You will not have to program a COMMREQ instruction in the slaves, but you will have to set up their ports for Modbus RTU slave in their hardware configuration.

And of course give each Slave port the proper Node number or ID.
See this for more: http://forums.ge-ip.com/showthread.php?p=72141#post72141

Versamax Modbus Communication

Dear Sir,

I've attached the pin diagram that i'm using for modbus communication. Still I failed to enable the communication between master & slave.

Although Program of master is working good i've checked it by MODBUS POLL tool software. But when I connect it with another versamax plc it didn't communicate. PLZ help...

unus said:

Dear Sir,

I've attached the pin diagram that i'm using for modbus communication. Still I failed to enable the communication between master & slave.

Although Program of master is working good i've checked it by MODBUS POLL tool software. But when I connect it with another versamax plc it didn't communicate. PLZ help...

Click to expand...

I see no pin diagram.
For cabling try this and be sure to have the terminating resistors properly installed.
You will find pin-outs for most GE-IP ports here: KB16495
Or here: For the optional Port 2 of the VersaMax Micro PLCs see GFK-1645 for details.

Hello All !!!]

Thanks You STEVE and RUSS. I've successfully configured the communication between two VERSAMAX PLC as Mater & Slave. Now I've just One more problem.

I've Use GFK-2220B Manual.

I've now Two Slave and One Master.

Problem#1:
At a Time the master just communicate with One slave and it do not respond to the other slave. So what changes I need to do in Program Please let me know

Problem#2:
I want to Read and write slave registers and I/O's simultaneously , but the Master failed to do it with the same time. It just process my one instruction at a time.

Modbus RTU only permits one transaction at a time. You issue a read command to slave #1 and wait for the response data. Then you issue a write command, with data, to slave #1. Then you issue a read command to slave #2 and wait for the response data. Then issue a write command, with data, to slave #2.
Repeat the cycle.

Of course, your sequence could be Read #1, Read #2, Write #1, Write #2 or any other permutation.

Each one of those transactions requires slightly different data in the %R registers associated with the COMMREQ instruction.. You should set the COMMREQ status word to zero before executing each COMMREQ instruction and wait for the COMMREQ status word to have a value of 1 before executing another COMMREQ instruction.

With COMMREQs the thing to remember is that there can be only one COMMREQ per port active at any given time.

> Send a COMMREQ to a port.
> wait for its Staus Register to become ">1" indicating it is complete, "=1" means without error.
> Now that port is ready for the next COMMREQ.
There are many variables involved in determining how fast data can be exchanged this way.

I want to use comm_req instruction.can any one help me out

Start by reading about it in Proficy ME then determine what port and protocol or smart module you want To communicate to with the COMMREQ and read its specific help file or manual on the subject. Next ask any detailed question on any part that is not understood. I suggest that you start a new thread for that.
Manuals can be found at the GE-IP support web site support.ge-ip.com

I have used blk_move word instruction to enable the port as modbus_master.But its not working.what shoult i do??

The BLK_MOV instruction is the first step. After that you have to execute the COMMREQ instruction using the data you set up in the BLK_MOV. Then you will need to execute another BLK_MOV/COMMREQ pair of instructions for each transaction between the Modbus master and slave.

Be sure that the COMMREQ instructions are enabled by one-shots.

thanks,wil try it.but if anyone one having a sample programme for the same plz share it.

The manual GFK-2220 has examples for Modbus RTU (serial) communications. The manual GFK-1541 has examples for Modbus TCP (Ethernet).

GE PLC Modbus RTU master communication issue

Dear All,

I am working with GE Versamax micro 20 PLC to read & write few data from a Modbus Slave device. The register address of slave starts from 432769, but I can enter maximum 32768 in Bulk move command in PLC, since it is 8 bit.

Kindly support me to read these modbus address from GE PLC.

Best regards,