Setpoint Calculations; Timestamp Configuration - Trane BACnet BCI-R Integration Manual

Setpoint Calculations

The equipment has the ability to perform two basic control functions:
•
•
When the unit is configured for discharge air control, it controls the temperature of the air leaving
the unit to the discharge air temperature setpoint.
When the unit is configured for space air temperature control, it controls the air temperature of the
space that contains the space air temperature sensor. This value may be provided by wiring the
sensor to the unit or via a sensor value provided by the BAS.
Figure 6
control. When the unit is in an occupied mode the active space temperature setpoint is calculated
based on the space temperature setpoint and the two setpoint offset values. In unoccupied mode,
the unoccupied heating and cooling setpoints are used as the active setpoint.
Figure 6. Setpoint calculations

Timestamp Configuration

The BCI-R controller has a software-derived clock that maintains the time and date. The controller
records a timestamp when an event or a change-in-state is detected by a BACnet object. However,
in the event of a power loss, the device does not maintain this time and date information. At power
up, the device time and date will default to 12:00 p.m., Jan 1, 1970.
To minimize the possibility that the unit timestamp is not representing the actual time, the BAS
should be set up to periodically synchronize the device time clock with the BAS clock using the
BACnet Device Management-TimeSynchronization-A service (BIBB DM-TS-A).
BAS-SVP09B-EN
• Upon completion of this action, the BCI-R will set the present value of the Diagnostic Reset
Command object back to the inactive state.
Space air temperature control
Discharge air temperature control
illustrates how the various temperature setpoints are calculated for space temperature
BCI-R Operation
15