ABB AquaMaster 3, Manual

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AquaMaster 3
Electromagnetic flowmeter
MODBUS Tables Supplement COI/FET2XX/MOD/TBL-EN 4
MODBUS Protocol
1.3 Register Usage
This section provides further information and worked examples of MODBUS protocol messages,
application data units (ADUs) and their responses for each of the Register ranges corresponding to
AquaMaster 3 data types.
Note: MODBUS data model register addressing starts from XXXX1 but within the MODBUS protocol
data unit (PDU) addressing starts from XXXX0.
Register addresses shown in the Register allocation tables (Appendix A) are MODBUS data model
register addresses.
1.3.1 RW 1-Bit
Read/Write access to single bit types.
Read Coils 1 to 14
Read all RW 1-Bit items
Request Message (Hex) Response Message (Hex) Error Message (Hex)
Address 01 Address 01 Function 81
Function 01 Function 01 Exception Code Exception Code
Starting Address Hi 00 Byte count 02
Starting Address Lo 00 Outputs status 00008-00001* 61
Quantity of Inputs Hi 00 Outputs status 00014-00009* 05
Quantity of Inputs Lo 0E CRC 50
CRC BD CRC 6F
CRC CE
*Coils 1,6,7,9,11 = 1
*Coils 2,3,4,5,8,10,12,13,14 = 0
Write Single Coil 3
var54: Display Net Total = ON
Request Message (Hex) Response Message (Hex) Error Message (Hex)
Address 01 Address 01 Function 85
Function 05 Function 05 Exception Code Exception Code
Output address Hi 00 Output Address Hi 00
Output Address Lo 02 Output Address Lo 02
Output Value FF Output Value FF
Output Value 00 Output Value 00
CRC 2D CRC 2D
CRC FA CRC FA