Application

Application Notes
Sequence of Operation – Summary
25
Siemens Industry, Inc.
Application Note
A6V11692053
Smart Infrastructure – Building Products
2019-04-01
Sequence of Operation – Summary
Overview
This application modulates the supply air dampers of the dual duct terminal box for
cooling, heating, and ventilation (for demand control ventilation a room air quality
sensor is required: QMX3.P74).
14069: Modulating Electric Heat and Hot Water Radiator (on DXR.x12)
14169: Demand Control Ventilation, Modulating Electric Heat and Hot Water
Radiator (on DXR.x12)
14369: Modulating Hot Water Heat and 1-Stage Electric Radiator (on DXR.x10
“ADXR”)
Terminal box airflow is maintained at the larger of ventilation airflow or the heating
or cooling airflows. The modulating (or staged) heat operates the heating coil to
maintain room temperature at setpoint.
The analog outputs for damper control (1DMPR POS, 2DMPR POS) are modulated
by respective airflow PID controllers. A modulating AO is used for heating (HTG EL
POS for modulating electric; HTG V POS for hot water).
Additionally, 14069 and 14169 each have a floating output for hot water radiator
(RAD V POS); 14369 has a binary output for a single stage electric radiator (RAD
EL POS).
Each duct can be configured to provide hot, cold (or both) airflow, and the source
for ventilation air can be configured to come from cold duct, hot duct, or both.
Additionally, the transition between heating and cooling is configurable for hot/cold
airflow mixing control or snap acting control. See Dual Duct Configurations for
detailed information on these topics.
PID controllers are provided for each of the following control elements:
⚫ Room heating demand
⚫ Room cooling demand
⚫ Supply air temperature reset for heating coil (14169 only)
⚫ VAV duct 1 airflow setpoint
⚫ VAV duct 2 airflow setpoint
⚫ Ventilation demand
(basic ventilation and/or demand control)
Inputs
⚫ Room temperature sensor (14169 also uses room air quality sensor)
⚫ Room temperature setpoint shift
⚫ Temporary Comfort button
⚫ GreenLeaf button
⚫ Differential pressure sensor, Duct 1
⚫ Differential pressure sensor, Duct 2
⚫ Supply air temperature sensor
⚫ Heating coil overtemperature detector (