KGL Operating Manual – VS 3010 BS
2018-07-02
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(C) In the case of falling pressure that is less than the setpoint plus 1.5 times the NZ and is greater than the
setpoint plus 0.5 times the NZ, no compressor actuation is performed.
(D)
compressor switching is performed in the NZ.
No
(E) At a pressure less than the setpoint value minus 0.5 times the neutral zone (NZ) and greater than the
setpoint value minus 1.0 times the NZ, and in the event of a
pressure change, the step switching
negative
mechanism unloads stages.
(F) At a pressure less than the setpoint minus 1.0 times the NZ, the step switching mechanism unloads stages
of the pressure change.
independently
(G) In the case of increasing pressure that is between the setpoint minus 1.0 times the NZ and is greater than
the setpoint minus 0.5 times the NZ, no compressor actuation is performed.
4.4.2.1 Neutral zone with compressor step control
If the low-pressure control Z1/Z2 is performed using step controllers, no compressor actuation is performed
while the control error is within a programmable neutral zone Z1/Z2. If the suction gas pressure is regulated
using a combined control, the neutral zone has no meaning.
4.4.2.2 Compressor control times for compressor step regulation
Compressor actuation only occurs if the control error has exceeded a specified value (Neutral Zone) and a
specific time for loading or unloading has elapsed.
The control time is calculated from the sum of a basic time tb and a variable time tv.
The variable time is inversely proportional to the control error. The higher the control error the shorter the
delay. In the case of maximum control error, the variable time tv = 0. In the case of declining control error, the
time tv is increased up to a specified maximum time. The basic time and the maximum variable time for the
shifting up (switching on) and shifting down (switching off) can be configured as parameters for each capacity
stage.
The switch-on and switch-off delay only starts outside the neutral zone. A compressor stage is loaded with the
delay time for number of running compr 1. The shifting down for step control always starts with the
delay of the first stage.
The calculation of the control times is identical for both temperature ranges. The variable control time tv = 0 if
