How to use MBMaster to verify basic modbus communications.

Issue
Using MBMaster to verify that a Modbus device is working.

Product Line
Modbus devices

Environment
Windows

Cause
MbMaster can be used to determine if a modbus device is working.

Resolution
Run this program from a DOS prompt.

For example here is a sample where I connect to a 6200 device at 19,200 baud. I am using the PC's COM2. The meter's Unit ID is 100 and it is configured to use the Modbus protocol. I am asking for Modbus address 44000 which provides the password for this meter. My meter's password is 0.

MBMaster provides quite a bit of diagnostic information which you can ignore in this case. Just look for the data from the register.

-=-=-=-=-=- Sample MBMaster -=-=-=-=-=-=-=-
H:\\Bin>mbmasterV21M3 -COM2 -B19200 -ID100 -SR44000 -NR1
MBMASTER v2.1M3:    Compiled at Jul 13 2001 04:13:57

Stripped BAUD from input: 19200
Stripped SR from input: 44000
Install ModPL
About to open ModPL with port COM2
Building request: modslave = 100
Modbus AL frame received: fc = 03
Modbus AL frame: startreg = 404000, #regs = 1
Register 404000: 0
Exiting.
-=-=-=-=-=- End Sample MBMaster -=-=-=-=-=-=-=-

• 

  Original article#9458

  Controlled

  All content © 1992-2007 Schneider Electric

---

Legacy KB System (APS) Data: RESL189023 V1.0, Originally authored by KBAdPM on 11/09/2007, Last Edited by KBAdPM on 11/09/2007
Related ranges: Modbus / JBus