ABB AquaMaster 3

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