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Appendix G
–
Modbus Communications
31
If No Parity has been selected, the number of stop bits can be set to 1 or 2 (S1 or
S2). S1 is used if the unit is communicating through a modem; otherwise, S2 is the
standard.
4. When the desired Protocol is displayed, press the MAX TEMP RESET (Middle)
button. This will show the current Address setting.
Pressing the ALARM (Top) button will step the display UP through the addresses.
Pushing the FANS (bottom) button will step the display DOWN through the
addresses.
Note: Legal addresses in Modbus mode are 1–255.
Pressing the MAX TEMP RESET (top) button will return the unit to normal operation
and save the settings.
If no button is pushed for 30 seconds, the unit will automatically return to normal
operation with the communications setup unchanged.
Modbus
Register
Data Returned When Register Is Addressed
Comments
40001
Temperature Left Phase
Normal temperature range is 0 - 255D in low byte
40002
Temperature Center Phase
A value of 8000H indicates invalid data
40003
Temperature Right Phase
40004
ITM Status
Bit 0 "1" = Some other bit is '1'
Bit 1 "1" = ON, Fan State
Bit 2 "1" = ON, Alarm State
Bit 3 "1" = ON, Trip State
Bit 4 "1" = ON, Buzzer State
Bit 5 "1" = ON, Manual Fan State
Bit 6 "1" = ON, Aux Relay 4 State
Bit 7 "1" = ON, Aux Relay 5 State
40005
Maximum Stored Temperature
Normal temperature range is 0 - 255D in low byte
40006
Phase with Max Stored Temperature
Bit 0 Always a "1"
Bit 1 A "1" indicates max stored temp was left phase
Bit 2 A "1" indicates max stored temp was center phase
Bit 3 A "1" indicates max stored temp was right phase
NOTE: There will always be only a
single "1" in bits 1, 2, or 3
40007
Temperature at Unit's Terminal Block
The low byte indicates the temperature at the
instrument terminal block in degrees C.
Temperatures below zero will show as zero
40008
Diagnostic Status
Bit 0 "1" = Some other bit is '1'
Bit 1 "1" = Failed A/D Converter
Bit 2 "1" = Failed Terminal Block Temperature Sensor
Bit 3 "1" = Failed EEROM
