User Manual

Functions
The controller acquires the room temperature with its integrated sensor and maintains
the setpoint by delivering three-position 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
Y
Out
[%]
XpH
w
0
100
3026D0 1
T [°C]
Y
Out
[%]
w
0
100
3026D02
T [°C]
XpK
T Room temperature w Room temperature setpoint
XpH Proportional band heating YB
OutB
Manipulated variable
XpK Proportional band cooling
Note: the diagrams only show the proportional part of the PI controller
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 tempera-
ture 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.
Automatic
changeover
CM
HM
T
W
[°C]
3026D03
16 28
M
CM Cooling mode
HM Heating mode
TB
WB
Water temperature
M Operating mode
Purging function
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.
Three-position
control signal
Outputs Y1 = opening, Y2 = closing and N = neutral are used to drive three-position
actuators with a maximum running time of 150 seconds from the fully closed to the fully
open position.
When commissioning the controller, an opening signal of 200 seconds is delivered,
followed by a closing signal of 200 seconds to ensure the actuator will be fully closed.
When the actuator has reached the position calculated by the controller, a waiting time
of 30 seconds is observed in order to stabilize the outputs.
The control outputs carry AC 230 V.
Energy saver
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.
2/8
Siemens Building Technologies Room temperature controller CE1N3026en
HVAC Products 12.06.2003