Testing Modbus Module from PC

Hi all!
I have Vipa CPU 214 and Modbus module for it with RS-485 interface (CP240). I configured CP240 as Modbus Slave and want to test it from my PC, i.e. to send some requests and get answers from module. How can I do that?
Thanks

Schtiel said:

Hi all!
I have Vipa CPU 214 and Modbus module for it with RS-485 interface (CP240). I configured CP240 as Modbus Slave and want to test it from my PC, i.e. to send some requests and get answers from module. How can I do that?
Thanks

Click to expand...

There are 2 easy solutions.

1. Get some free Modbus testing software
2. Use a generic SCADA demo
-------------------------

For # 1 you can use:

Modscan or Modscan32

or

SimplyModbus

but there are many more.

For # 2 (which is what I do)

Use ANY SCADA you can get your hand on. They all have a Modbus driver and you can use there demo disk to do this.

Google for "SCADA demo" and you can get one free.

Ok, thanks. But PC doesn't have RS-485 interface. What cable (or what tools) should I use to connect my PC with RS-485 Modbus module?

For 2 wire, half duplex RS-485, I use a B&B Electronics port powered unit 485SD9TB for bench top testing, although I ALWAYS use the B&B 12Vdc power supply with it. In fact, yesterday I had to use a laptop whose serial port was functional but the serial port would not power the converter. I thought the port was bad and then noticed the power supply wire had broken off. Duh . . . Without the 12Vdc the converter wouldn't work, which is more typical than atypical with 'port powered' converters and laptops.

This model does not have isolation so I never use it for permanent installations. For permanent installations I always use isolated converters.

The DB-9 fits the PC connector and the terminal strip has screw terminal connections for field wiring.

It has worked up to 38.4K baud without any problem.

There are tons of cheap converters on eBay. Maybe they work, maybe they don't. I don't know. I stay with what I know works.

http://www.bb-elec.com/bb-elec/literature/485sd9tb-3803ds.pdf
Dan