Please help me to understand the ABB Modbus mapping. I need to talk with a Honeywell TDC3000 through a serial Interface. The ABB Modbus mapping addresses seem to all be in the 4000x.x range for everything (discrete, analog, reads, writes). Our Honeywell system uses the standard Modbus addressing (1-9999 for discr R/W, 10001-19999 for discr Read Only, 30001-39999 for R/W Analog, and 40001-49999 for read only analog) I do not understand the ABB map that has all info in 4xxxx range followed by a decimal. Can anyone shed some light?

 

It is reasonably common for companies to provide access to all of their product's data (be it discretes, inputs, outputs, etc.) via 4X holding registers, as they are the one common denominator in all Modbus devices/drivers.

It may not be the case for your ABB product, but frequently the notation "4ABCD.X" would indicate a reference to "bit X" in holding register "ABCD".

Darrin Hansen
ICC, Inc.

 

Hi there,

With the ACS800 drives reg 40001 = control word, 40002 = Ref 1, 40003 = Ref2, 40004 = status words, 40005 = Actual, 40006 = Actual 2. In the firmware manual pg. 205& 206 give the bit description for the control & status words.

Hope this helps,
Stanley