Application

Sequence of Operation

Control Temperature Setpoints

Siemens Industry, Inc.

Application Note, App 6663

140-1109

2014-10-27

CTL STPT Using Standard/Absolute Mode (Digital Room

Unit, Revision 26 and later)

Digital Room Unit (2200/2300 Series Firmware Revision 26 and later)

For all new digital room units, the value displayed and reported by the room unit is

linked to the current heat/cool mode. When the mode changes, the value is

automatically updated based on the new heat/cool mode.

When STPT SPAN is set to 0, the room setpoint adjustment on the digital room unit will

function in a standard mode. The range of the adjustment will be based on RM STPT

MIN and RM STPT MAX.

CTL STPT is set equal to RM STPT DIAL. The values for RM STPT MIN and RM

STPT MAX will be applied to limit RM STPT DIAL before it is copied into CTL STPT.

CTL STPT Using Warmer/Cooler Mode (Digital Room Unit,

Revision 26 and later)

Digital Room Unit (2200/2300 Series Firmware Revision 26 and later)

NOTE:

The warmer-cooler function is only available with BACnet PTEC controllers (standard

66xx apps).

When STPT SPAN is set to a value > 0, the room setpoint adjustment on the digital

room unit will function in a warmer/cooler mode. The range of the adjustment will be

calculated based on the current DAY CLG STPT or DAY HGT STPT and the STPT

SPAN value. This will allow the Room Setpoint Dial to be incremented up or down from

these setpoints by STPT SPAN.

CTL STPT is set equal to RM STPT DIAL. The values for RM STPT MIN and RM

STPT MAX will be applied to limit RM STPT DIAL before it is copied into CTL STPT.

When SPTP SPAN > 0, the minimum and maximum values for RM STPT DIAL are

calculated as follows:

 Minimum lowest adjusted setpoint value is equal to DAY CLG STPT or DAY HTG

STPT - STPT SPAN

 Maximum highest adjusted setpoint value is equal to DAY CLG STPT or DAY HTG

STPT + STPT SPAN

Example in Cooling Mode

If the STPT SPAN is set to 2.0 degrees, and the DAY CLG STPT is 76°F, you can step

up or down the room unit to adjust the RM STPT DIAL from 74°F to 78°F.