Control Method - Zehnder Rittling Option Box V2 Installer Manual

16

Control method

Steer
Device
0-10V output
To steer means the output of the connected
device directly influences the volume. Typically,
this should be used for steering devices, such as
SAG 0-3, SAG 0-5 or SAG 0-M.
Sensors with steering add-ons, such as 0-10V
CO sensors with presets, cannot be used for
2
control. The method of interaction must be to
steer, since the presets are fixed sensor outputs,
which must directly influence the volume.
Control
Setpoint
0-10V
In case of control with a CO
sensor, the input at 0% is the maximum output of
the sensor and the input at 100% is the minimum
input of the sensor. The reason for this is that a
control tries to remove an error, which is defined
as the setpoint minus the measured value. If the
measured value is too high, the error is negative,
whereas a positive action (increased volume) is
required. This means the input for the control
needs to be inverted.
Proportional controller
error
+
-
measured value 0-10V
sensor or a humidity
2
ComfoAir Q
Steering
Settings
In case a sensor would be connected, this would
mean that a high sensor level corresponds with
a high volume. If a 0-2000ppm CO
0V@0ppm and 10V@2000ppm is connected,
this would mean that at 1000ppm, 50% would
be the output of the steering. The volume would
be 50% on the scale of the volume at which
the sensor started (preset 1 typically) and the
maximum allowable volume (preset 3 typically).
To steer means there is no control, so the air
quality is not guaranteed. If the requirement
would be for the ventilation to guarantee a
maximum of – for example – 800ppm, control
should be selected as a method.
Proportional band, error
Integral controller
Integral time, sum of errors
The CO
the CO
tries to get rid of the error. The steady state CO
level for any number of persons will be the same,
unless the ventilation system cannot deliver
enough air. In case of control with a third-party
pressure sensor, too high pressure (negative
error) requires reduced volume. Therefore, there
is no need to invert the input.
ventilation
ComfoAir Q
ventilation
Sensor
sensor controlling the ventilation means
2
is kept at a constant level. The control
2
sensor, with
2
0-10V
2
EN - 31