Application

Application Notes
Sequence of Operation – Summary
26
Siemens Industry, Inc.
Application Note
A6V11692055
Smart Infrastructure – Building Products
2019-04-01
Room operating modes
The operating mode of the controlled space is applied according to schedule or
room occupant input. The room operating modes are:
⚫ Comfort (occupied)
⚫ Pre-Comfort (standby)
⚫ Economy (unoccupied)
⚫ Protection (e.g. extended holiday)
Comfort mode is applied per schedule via central command for each VAV box. A
pushbutton ("Comfort button") is provided at each room operator unit to
temporarily override the Economy mode and place the room into occupancy
(Comfort) for a period of time (120 min configurable). Prior to occupancy a request
for warm-up or cool down can be provided via central command.
Each room operating mode has a configurable ventilation mode (e.g. minimum
ventilation, DCV) and a separate minimum room air volume flow (e.g. 150 cfm,
configurable).
Related objects:
⚫ RM OP MODE – Room operating mode (ROpMod)
⚫ OP MOD CMD – Central operating mode command value (CenOpModCmdv)
⚫ CMF BTN – Comfort button (CmfBtn)
⚫ WARM UP REQ – Warm-up request (WarmUpReq)
⚫ COOL DN REQ – Cool down request (CoolDwnReq)
Room temperature setpoint determination
a)
The application evaluates operating modes, setpoints and offsets to calculate and determine
the current ("effective") room temperature heating and cooling setpoints.
b)
The heating and cooling setpoints can be separately configured for each room operating
mode.
c)
Setpoints can be commanded manually or via central command.
d)
The room operator unit is configured to allow manual adjustment of Comfort and Pre-Comfort
control setpoints. The shift limit is +/- 5.4°F, configurable. Manual adjustments at the room
unit [RM TEMP SHFT] will shift the heating and cooling setpoints up or down together,
keeping the width of the deadband constant.
e)
Pre-Comfort heating and cooling setpoints are each based on a heating or cooling Comfort
offset value; each Pre-Comfort setpoint has its own configurable offset differential (default
2°F).
f)
During Comfort and Pre-Comfort modes, the room unit will display the current heating or
cooling setpoint.
g)
During Economy and Protection modes, the room unit will display the last Comfort or Pre-
Comfort heating or cooling setpoint.
h)
When in deadband (no heating or cooling) – during any mode – the room unit will display the
last Comfort or Pre-Comfort heating or cooling setpoint.
i)
The heating/cooling state is displayed as an icon on the room unit. When in deadband, the
space for the icon is blank to indicate that heating and cooling are both off.
Related objects:
⚫ OP MODE EFF – Present operating mode (PrOpMod)
⚫ RM TEMP EVAL – Room temperature (RTemp)
⚫ HTG STPT EFF – Present heating setpoint (PrSpH)