The MP Series controller sensor bus allows SmartX Sensors to be connected to the controller.
The sensor bus is a proprietary RS-485 bus, which provides both 24 VDC power supply (2 W) and communications for the sensors.
The maximum total length of the sensor bus is 61 m (200 ft). The sensor bus uses a Cat 5 (or higher) unshielded, straight-through wired cable with eight conductors (four twisted pairs) and RJ45 connectors. The wire size (cross-sectional area) should be 22 to 26 AWG (0.34 to 0.14 mm²). When the MP Series controller is installed in a space that handles conditioned air or return air, the sensor bus cables and IP network cables frequently must be plenum-rated to meet applicable building codes. For more information, see Wiring .
You can connect a single SmartX Sensor to the MP Series controller sensor bus port, or you can connect two to four SmartX Sensors in a daisy-chain configuration.
When connecting SmartX Sensors to the MP Series controller sensor bus through a daisy-chain configuration, it does not matter if the incoming and outgoing cables are connected to one or the other sensor bus port on the SmartX Sensor.
The maximum number of SmartX Sensors that can be connected to an MP Series controller is variable depending on the power consumption for the selected SmartX Sensor model and the combination of cover and sensor base type.
When calculating the power consumption to validate your sensor bus configuration, ensure that you add the power consumption (mW) for all SmartX Sensor models, sensor bases, and covers used on the sensor bus to determine the total power consumption. The sensor bus can supply maximum 2000 mW. SmartX Sensor combinations totalling more than 2000 mW are not supported. The following table can be used for calculating the total power consumption.
Description |
Model Number |
Power (mW) |
Sensor base with temperature sensor |
SXWSBTXXXSXX |
90 |
Sensor base with temperature and humidity sensors |
SXWSBTHXXSXX |
90 |
Sensor base with temperature and CO 2 sensors |
SXWSBTXCXSXX |
490 |
Sensor base with temperature, humidity, and CO 2 sensors |
SXWSBTHCXSXX |
490 |
Blank cover |
SXWSCBXSELXn a |
0 |
Blank cover with occupancy sensor |
SXWSCBPSELXn a |
20 |
3-button cover (buttons for override and setpoint control) |
SXWSC3XSELXn a |
190 |
3-button cover (buttons for override and setpoint control) with occupancy sensor |
SXWSC3PSELXn a |
210 |
Touchscreen display cover |
SXWSCDXSELXn a |
190 |
Touchscreen display cover with occupancy sensor |
SXWSCDPSELXn a |
210 |
Complete SmartX Sensor model with temperature sensor, buttons for override and setpoint control, and LCD display cover |
SXWSATXXXSLn a |
80 |
Complete non-communicating b SmartX Sensor model with resistive temperature sensor (10 kohm type 3 thermistor) and blank cover |
SLAnXXX c SXWSATXXXRXX d |
0 |
eCommission Bluetooth Adapter e |
SXWBTAECXX10001 |
300 |
To summarize the power conditions, the sensor bus supports the following key SmartX Sensor combinations:
Blank covers: Up to four sensors of any combination of sensor base types
3-button and touchscreen covers:
Up to two sensor bases with CO 2 option
Up to four sensor bases without CO 2 option
SmartX LCD temperature sensors: Up to four sensors are supported
Each SmartX Sensor has two 2-position DIP switches, which are used to give the sensor a unique address on the sensor bus. An incorrectly configured or improper DIP switch can cause two sensors to have the same address on the sensor bus, which means that both sensors will be offline. For more information, see SmartX Sensors .
SmartX Sensors connected to the MP Series controller sensor bus through a daisy-chain configuration can be assigned addresses regardless of the order in which the sensors appear in the daisy chain. For example, sensor number 1 can have the address 6, sensor number 2 can have the address 4, and so on.