Table 2 Read Status
BIT
d1
d2
d3
b.7 = 1
RTD1 Open Fault
RTD2 Open Fault
High Fixed Temp Fault
b.6 = 1
RTD1 Shorted Fault
RTD2 Shorted Fault
Low Fixed Temp Fault
b.5 = 1
RTD1 Open
RTD2 Open Warn
High Temp Fault
b.4 = 1
RTD1 Shorted
RTD2 Shorted Warn
Low Temp Fault
b.3 = 1
RTD3 Open Fault
RTD2 Open
Low Level Fault
b.2 = 1
RTD3 Shorted Fault
RTD2 Shorted
High Temp Warn
b.1 = 1
RTD3 Open
Refrig High Temp
Low Temp Warn
b.0 = 1
RTD3 Shorted
HTC Fault
Low Level Warn
BIT
d4
d5
b.7 = 1
Buzzer On
RTD2 Controlling
b.6 = 1
Alarm Muted
Heat LED Flashing**
b.5 = 1
Unit Faulted
Heat LED On**
b.4 = 1
Unit Stopping
Cool LED Flashing**
b.3 = 1
Unit On
Col LED On**
b.2 = 1
Pump On
0
b.1 = 1
Compressor On
0
b.0 = 1
Heater On
0
**LED bits in REQ STATUS1 byte d5
LED State
LED Flashing
LED On
OFF
0
0
ON
0
1
FLASHING
1
1
Invalid
1
0
b.7 = most significan bit
b.0 = least signifcant bit
Table 3 Qualifier Byte
10 hex
0.1 precision, no units of measure
20 hex
0.01 precision, no units of measure
11 hex
0.1 precision, °C units
21 hex
0.01 precision, °C units
Example: The temperature of 45.6 °C would be represented by the qualifier 11 hex, followed by the 2 bytes 01
C8 hex (456 decimal).
Appendix B
B - 5