Carrier PC211 Start-Up, Operation And Maintenance Instructions Manual page 237

Options Modules (8-Input)
The options modules are optional additions to the PIC, and are used to add temperature
reset inputs, spare sensor inputs, and demand limit inputs. Each option module contains 8
inputs, each input meant for a specific duty. See the wiring diagram for exact module wire
terminations. Inputs for each of the options modules available include the following:
Option Module 1
4 to 20 mA Auto. Demand Reset
4 to 20 mA Auto. Chilled Water Reset
Common Chilled Water Supply Temperature
Common Chilled Water Return Temperature
Remote Temperature Reset Sensor
Spare Temperature 1
Spare Temperature 2
Spare Temperature 3
Option Module 2
4 to 20 mA Spare 1
4 to 20 mA Spare 2
Spare Temperature 4
Spare Temperature 5
Spare Temperature 6
Spare Temperature 7
Spare Temperature 8
Spare Temperature 9