User Manual

2/8
Siemens Building Technologies Room temperature controller CE1N3025en
HVAC Products 12.06.2003
Functions
The controller acquires the room temperature with its integrated sensor and maintains
the setpoint by delivering DC 0…10 V control commands to the valve. The controller
provides PI control. The proportional band in heating mode is 4 K and in cooling mode
2 K. The integration time is 5 minutes.
Heating mode Cooling mode
Y10 [%]
XpH
w
0
100
3025D01
T [°C]
Y10 [%]
w
0
100
3025D02
T [°C]
XpK
Note: the diagrams only show the proportional part of the PI controller.
The room temperature setpoint can be limited in increments of 1 K by making use of
the minimum and maximum limitation facility. Arbitrary setpoint readjustments can
thus be prevented.
The water temperature acquired by the changeover sensor (QAH11.1 + ARG86.3) is
used by the controller to switch from heating to cooling mode, or vice versa. When the
water temperature lies above 28 °C, the controller switches to heating mode, below
16 °C it switches to cooling mode. If, immediately after switching on, the water tem-
perature lies between the 2 changeover points, the controller will start in heating
mode. The water temperature is measured at minute-intervals and the operational
status updated.
CM
HM
T
W
[°C]
3025D03
16 28
M
The task of the changeover sensor is to initiate the change from heating to cooling
mode even if the two-port valves are shut down for a longer period of time. To ensure
this function, the valves are opened for one minute at 2-hour intervals during off
hours.
The fan is switched to the selected speed via control output Q1, Q2 or Q3.
When the function “Temperature-dependent fan control“ is activated (can be selected
with DIP switch no. 1), the fan is switched on / off depending on the temperature, that
is, together with the valve.
It is switched off by
• leaving the heating or cooling sequence, provided the function “Temperature-
dependent fan control “ is activated, or
• manually changing to standby
, or
• activating an external operating mode changeover switch, provided plant condi-
tions do not call for energy saving, or
• turning the controller’s power supply off.
Energy saver
Automatic
changeover
Purging function
Fan operation
T Room temperature w Room temperature setpoint
XpH Proportional band heating Y10 Manipulated variable «Actuator»
X
p
K Pro
p
ortional band coolin
g
CM Cooling mode
HM Heating mode
M Operating mode
T
W
Water temperature