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Heatcraft Mohave Control Modbus Definitions
Heatcraft Mohave Control Rev. 17
10/4/2016
NOTE: For this device, ModBus message frames must be no larger that 256 bytes
NOTE: For ModBus commands, temperatures are always degrees F, pressures
are always psia, and times are always 24-hour HHMM
Discrete Inputs -
CMD 0x02 (Read)
Input Address Byte Addr. Bit Addr.
"Enter" pushbutton
"Clear/Test" pushbutton
"Program Review" pushbutton
"Force Service" pushbutton
"Monitor" pushbutton
"Force Defrost" pushbutton
"Reset Time" pushbutton
Service Switch contacts
Safety Switch contacts
CU Suction Pressure switch contacts
T-Stat contacts 10 1 2
BeaconII I/F current sense 11 1 3
Remote Defrost switch contacts 12 1 4
Coils -
CMD 0x01 (Read), CMD 0x05 (Single Write)
Coil Address
Byte Addr. Bit Addr.
CMD 0x0F (Multiple Write)
Beacon "Low Pressure Switch" output
Evaporator Heater relay
Liquid Line Solenoids relay
Evaporator Fan relay
Condenser Fan 4 relay
Condenser Fan 3 relay
Condenser Fan 2 relay
Condenser Fan 1 relay
Alarm relay
Compressor relay
Bypass Valve relay
Suction Solenoid relay
Defrost Solenoid relay
3-Way Valve relay
Input Registers -
CMD 0x04 (Read)
Data Type
Word Addr. Label
Suction Temperature (-55 to +125 degrees F) Word, signed 0
SucT
Ambient Temperature (-55 to +125 degrees F) Word, signed 1
AMBT
Auxilliary Temperature (-55 to +125 degrees F) Word, signed 2
AUXT