KGL Operating Manual – VS 3010 BS
2018-07-02
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4.6.1.8 Output of the opening degree for tandem operation
Valve enable with active tandem operation (parameter ”Tandembetr.” =”YES”, menu 3-2-3).
If tandem operation is active, valve 1 is enabled as soon as the PID controller operating independently of the
enable function has calculated an opening degree greater than zero. If the controller calculates an opening
degree of zero, valve 1 is disabled via the enable output.
Valve 2 is enabled when the configurable opening degree threshold "enable V2” (menu 3-2-3) is exceeded. If
the configurable opening degree threshold ”Disable V2” (menu 3-2-3) is undercut, valve 2 is disabled again. V2
will now only be enabled when V1 is enabled.
In order to prevent excessively high relay switching frequency, a minimum enable and disable time applies for
each valve. The minimum enable time for V1 and for V2 is 35 seconds. The disable times for both valves are
35 seconds. If V2 is not enabled, the input signal during active tandem operation (0 V…10 V output) is
doubled.
UA = ÖGPID * 2 for disabled V2
If both valves V1 and V2 are enabled, the calculated correcting variable is output directly.
UA Output voltage for valve opening degree input signal
ÖGPID Correcting variable calculated by the PID controller
The following diagram illustrates the enable processes during tandem operation.
4.6.1.9 Limiting the opening degree
An upper limit for the opening degree output by the cascade controller can be set using this function. This
opening degree will never be greater than the maximum value set using the parameter “Maximaler ÖG” (menu
3-2-3).