Issue
Is there any way to connect two smart sensors (TTS-SD-LCD-1) to one VAV controller b3855-V or other BACnet control board?
Environment
- CyberStation
- Bacnet
- b3855-V
- Smart Sensor
Cause
Customer wants two smart sensors per b3 controller.
Resolution
Two smart sensors should not be connected to a single b3 controller. The smart sensor uses a 3-wire connection to the controller.
The controller communicates with the keypad and the display of the Smart Sensor device over a single wire (the PWR connection). The RET line is the return for both the communications line and the internal thermistor. The input signal is the active lead from the Smart Sensor thermistor. This input must be configured as a general Temperature input.
Among other possible problems, the temperature reading would be incorrect if two sensors were connected to one controller.