1400 modbus to VFD

hello

im trying to control 3 G3 Dura VFD with a AB 1400 using MODBUS RS485RTU

this is my 1st time I've played with Modbus on a AB and using MSG

what i want to do is all 3 drives to run independently from each other on off speed also i want to be able to monitor the load

here is a little file i'm using to test with 1 drive

43332 run
48460 load meter

i'm not 100% if its my program or wiring or VFD setup


thanks for your help

At first glance the program looks OK.

Are you sure the target drive is set for Modbus Slave ID 3 ?

What is the physical wiring like from the Channel 0 port to the drive ? Usually the 1763-NC01 cable is the way to go.

You have correctly set the port for "No Handshaking (485 Network)" to use the RS485 pins 1 and 8 on the Channel 0 plug.

On RS485 systems, Rule #1 is always to swap the data wires and try it both ways.

I would test this by switching the port back to RS-232 and connecting up a PC as a Modbus RTU Slave tester.

Chipkin Automation's Modbus Parser and Modbus Scanner are great tools, but not what you need here. Do go download their "Modbus for Field Technicians" booklet.. it's outstanding.

There are a handful of Modbus RTU slave simulators on the market, but I like the simplicity of the Win-Tech ModSim program.

http://www.win-tech.com/html/modsim32.htm

thanks i download modbus sim got it running on a different computer

with the sim off line and the 1400 and the VFD on nothing happens but when i get the sim online as the same device as the VFD #3 the VFD will start working runs stops from the 1400 N7:0 and the sim will update what the 1400 is doing. as soon as i disconnect the sim nothing works so i do have a setting off somewhere by where

thanks

I was suggesting switching to RS-232 for testing with the simulator, then switching back to RS-485 for testing with the drive.

Describe in detail how you have this wired up, because I can't picture how you could have both the drive and simulator connected at the same time.

i got one of these with the drives

http://www.automationdirect.com/static/specs/fzipcommdistmodules.pdf

i got the screw terminal wired into the plc
port 1 goes VFD
port 2 goes on the sim


down the road ill have all 3 drives on it

I'm back to try aging ill let you know

thanks aging

got it working 100% i added a ground to the RS485 pin 2 on the both sides

not sure why


thank you for your help