Control Method - Zehnder Option Box Manuel De L'installateur

16 Control method

Steer
Device
0-10V output
To steer means, the output of the connected device
directly infl uences 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 control. The
method of interaction must be to steer, since the presets
are fi xed sensor outputs, which must directly infl uence
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 defi ned 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.
Steering
Proportional controller
Proportional band, error
error
Integral controller
Integral time, sum of errors
measured value 0-10V
-sensor or a humidity
2
ComfoAir Q
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
and 10V@2000ppm would be connected, this would
- mean, that at 1000ppm, 50% would be the output of the
2
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.
The CO sensor controlling the ventilation means
2
the CO is kept at a constant level. The control tries
2
to get rid of the error. The steady state CO
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
-sensor, with 0V@0ppm
2
ComfoAir Q
ventilation
Sensor
0-10V
level for
2
EN - 29