problems communicating to ABB drive

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Thread Starter

Timo Tuokkola

We just acquired an ABB ACS600 demonstration unit along with an NMBA-01 Modbus adapter unit so that I could test communications between our controller and the ABB drive. I have made all of the power connections, and connected our controller to the drive through the adapter. I have set up the drive parameters so that it knows there is a fieldbus adapter present. I am now experiencing the following problem:

As soon as I send a query from our controller to the drive, the ERROR LED on the adapter comes on and stays on continuously. The receive LED on the adapter continues to flash whenever I send a message to the drive, and the bad messages counter on the drive continues to increment. If I send a message to the drive using incorrect parity, both the ERROR and receive LED's flash briefly, then go out.

Does anyone know if there is any way an error in what I am sending would cause the ERROR LED to come on solid, or would this only be caused by a hardware failure in the adapter module?
 
V
Please make sure that you are using RS485Modbus for communicating to the ACS600,both the physical connection as well as the port setting of the Master controller, also do not try to read the 4X registers from ACS600 which are not assigned or reserved.

We are succesfully communicating with ACS600 (1100KW) using RS485 Modbus from our PLCs.

Regards,

Vinod Kumar
Manager, Instrumentation & Control
A A Engineering Services
Doha, Qatar.
 
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Timo Tuokkola

The physical connection is definitely RS485, as our controller only has an RS485 serial port. The controller should also be using Modbus RTU protocol, since I wrote the communication routines myself specifically to do that. I don't think that the problem is trying to read from an invalid register either, since the documentation says I should be receiving a response from the drive indication this and I am receiving nothing back from the drive.
 
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Robert Dusza

Timo,

We installed some ACS400 Series drives here and we had a problem communicating to the units. The issue was how we accessed the addresses for MODBUS. If there are any gaps is a list of parameters, the ABB drive will send back nothing. We were able to prove this by reading one register at a time and then setting up a range to read. If there were missing registers like 26.01 to 26.05, 26.04 is missing, we would not receive any info. Address 26.01 to 26.03 and 26.05 with separate commands, we were successful.

I hope I explained so you can understand the logic.

Bob


Robert J. Dusza, Jr.
Project & Technical Support Manager
(V) 1-860-647-3219
(F) 1-860-647-3150
E-mail - [email protected]
Manchester Water & Sewer Dept.
125 Spring St. P.O. Box 191
Manchester, CT 06045-0191
 
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