User's Manual

Operation
3A1149D 23
Secondary DGM Analog Inputs
Set Zone Temperature
The external control device interfacing with the DGM
can use a varying voltage to specify the desired setpoint
for the zone. See Secondary DGM Pin Assignments
on page 12.
To calculate the voltage to use based on the desired
temperature in degrees Fahrenheit:
Voltage = 0.074 x °F - 4.074
For example, the voltage for 86°F would be:
Voltage = 0.074 x 86 - 4.074
= 2.29
To calculate the voltage to use based on the desired
temperature in degrees Celsius:
Voltage = 0.133 x °C - 1.707
For example, the voltage for 30°C would be:
Voltage = 0.133 x 30 - 1.707
= 2.28
To set the zone temperature:
1. Calculate the voltage to use.
2. Set the desired “Set Zone Temperature” Analog
Input to the calculated voltage and hold.
3. After 185 mS, pull high the corresponding “Accept
Zone Setpoint Change” Digital Input for 185 mS
then release.
4. Check the Zone Temperature Setpoint Rejected bit.
If it is asserted, check the ADM.