AERCO Control System (ACS)
APPENDIX H:
ACS Modbus Address Assignments
11/22/2017
AERCO International, Inc.
•
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APPENDIX H: ACS MODBUS ADDRESS ASSIGNMENTS
IMPORTANT!
All Modbus addresses specified in this manual are written generically in hexadecimal format.
However, many Building Automation Systems utilize another form of addressing where:
40001 is added to the generic address for a Holding Register address.
AND
30001 is added to the generic address for an Input Register address.
Be sure to check the addressing scheme being used by the BAS that is being interfaced to the
ACS.
H.1
ACS CONTROLLER STANDARD INPUT REGISTER ASSIGNMENTS
The Read Only Input Register assignments for the ACS are listed in Table H-1 which follows:
TABLE H-1: ACS Standard Input Register Address Mapping
Modbus Data
Address Decimal
(Hex)
Menu Item
Units and Range
Default/
Comments
0 (0x0000)
(Reserved)
1 (0x0001)
Header Temperature
40 to 220°F
2 (0x0002)
Outside Air Temperature
-60 to 120°F
3 (0x0003)
Indoor Air/Return Temperature
40 to 220°F
4 (0x0004)
Fire Rate Out
0 to 100% (out to boilers)
5 (0x0005)
Header Set Temperature
40 to 220°F
6 (0x0006)
Network Address
128 to 247
Default = 128
7 (0x0007)
Total Boilers Fired
0 to 32 (for ACS)
8 (0x0008)
Total Boilers On Line
0 to 32
9 (0x0009)
(Reserved)
10 (0x000A)
Fault/Message Code
0 to 65535
Bit:
0 = Outside Air Sensor
1 = Header Sensor Error
2 = Interlock 1 Error
3 = Interlock 2 Error
4 = Indoor Air Sensor Error/
Return Sensor Error
5 = 4-20mA Input Error
