Gira KNX 2139 00 Product Documentation page 66

Valve outputs | Valve output - General
Often, control circuits are subject to non-constant changes in the setpoint presetting
(e.g. frost protection, night operation, etc.) or short-time interference (e.g. measured
value deviations due to brief opening of windows or doors near the sensor). For the
setting of the scanning ratio of the required command value to take place as quickly
and correctly in these cases, even with a longer set cycle time, without any negative
impact on the reaction time of the control section, the actuator uses a special method
for continuous command value adjustment.
The following cases are taken into account...
– Case 1
Command value change, e.g. from 80% to 30%, during the opening phase of
the valve (see figure 8).
Before the reception of the new command value (30%), the old setpoint (80%)
was active. The new command value is received during the opening phase of
the valve. At this point, the actuator detects that it is still possible to shorten
the opening phase, so that it corresponds to the new command value (30%).
The cycle time is not affected by this operation.
The new duty factor is set immediately after the reception of the new com-
mand value.
Image 8: Example of a command value change 80% -> 30% during the opening
– Case 2
Command value change, e.g. from 80% to 30%, during the closing phase of
the valve (see figure 9).
Before the reception of the new command value (30%), the old setpoint (80%)
was active. The new command value is received during the closing phase of
the valve. At this point, the actuator detects that it is still possible to extend the
closing phase, so that it corresponds to the new command value (30%). The
cycle time remains unchanged, but the starting time of the period is shifted
automatically.
The new duty factor is set immediately after the reception of the new com-
mand value.
Image 9: Example of a command value change 80% -> 30% during the closing phase
Heating actuator 6-gang with controller | Order no. 2139 00 | 21393100
phase of the valve
of the valve
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