Considerations On Temperature Signals - HMS Networks Intesis IN485FGL001I000 User Manual

Considerations on Temperature Signals

NOTE
2
The names of the Modbus registers provided in this section are for reference purposes only; pay
attention chiefly to their numerical addresses.
HOW THE VIRTUAL TEMPERATURE FUNCTION WORKS
When the Virtual Temperature function is active, the gateway is constantly applying the following formula:
S = T – (T – S )
AC AC BMS BMS
Where:
• S : Recalculated temperature setpoint sent to the indoor unit after the gateway applies the formula.
AC
• T : Indoor unit's reference temperature.
AC
• T : Ambient temperature reported by the sensor connected to the BMS side.
BMS
• S : Temperature setpoint requested from the BMS side.
BMS
Once activated, the Virtual Temperature function recalculates the setpoint when any of these values changes.
HOW TO ACTIVATE THE VIRTUAL TEMPERATURE FUNCTION
Follow this procedure:
1. Write the desired setpoint temperature in the Setpoint_command BACnet object/Temperature setpoint
Modbus register (protocol address 4, PLC address 5).
2. Read the temperature value reported by a temperature sensor from the BMS side.
3. Write this value in the RoomTemperature_command BACnet object/Input sensor temperature Modbus
register (protocol address 22, PLC address 23).
Once the gateway receives valid values for these objects/registers, the Virtual Temperature function is
automatically activated.
NOTE
When starting up the gateway, the dedicated object/register to write the ambient temperature
perceived from the BMS side reports a value of -32768 (0x8000). For BACnet, this object
is RoomTemperature_command (Analog Output). For Modbus, this register is Input sensor
temperature (R/W) (protocol address 22 / PLC address 23).
FOR BACNET
When starting up the gateway, the Present_Value property for the RoomTemperature_command
object is 0, and the Reliability property displays UNRELIABLE_OTHER (7). This means that no external
temperature reference has been provided to the object, so the system is not applying the Virtual
Temperature function. However, after receiving the first value, the Reliability property changes to
NO_FAULT_DETECTED (0). After that, any value can be used in the temperature range, including 0.
9.1. Considerations on Temperature Signals
NOTE
You can set the temperature signals in degrees Celsius or Fahrenheit via the DIP switch SW2. More
information in DIP switches (page
USER MANUAL Version 1.0.9
9).
IN485FGL001I000 Gateway
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