ECKELMANN VS 3015 CT, Инструкция по эксплуатации, Страница: 26 / 219

Firmware V1.41 V1 08.11.2022 26/219
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The basic time can be configured and is always constant.
Variable Time
The variable time can be configured and is variable. The value range is between 0 and the configured value (in
seconds). The duration of the variable time is calculated depending on the control constant. An example for this
with a basic time of 20 seconds and a variable time of 200 seconds. The control constant is parametrised to 10
K.
Parametrisation of control times
The basic time and the maximum variable time for the shifting up (switching on) shifting down (switching off)
can be configured for each capacity stage.
There are separate control time parameters for day and night operation with separate control constant in
each case.
Day control times are located in the menu 3-1-2-3
Night control times are located in the menu 3-1-2-4
A compressor stage is activated 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.
5.4.3 Control Algorithm with LP Combined Control
The measured low pressure measured using an A/D converter is compared with the setpoint:
Control error = Actual value (t
0_act
) - Setpoint (t
0_setp.
)
Depending on the control error, a control variable is calculated which controls the speed of the compressor as a
0-10 V signal. As the controller functions as a PI controller, a P-component and an I-component are calculated
using the configurable factors, P-factor and I-factor (menu 3-2-1-1).
P-component Calculation
P
Quota
= P value * Control error
I-component Calculation:
The P-component acts immediately on the speed in the case of a pressure change. The remaining control error
is minimised by infinitely increasing or reducing the input signal (ramp function). The adjusting speed of the
ramp (I-component of the controller) is dependent on the control error. Too high a ramp speed results in
constant overshoot of the suction pressure.
Too low a ramp speed results in the suction pressure setpoint only being reached after a long time delay. The
controller is then too slow. In order to adjust the I-component to the system, the ramp speed can be adjusted
using a configurable I-factor (menu 3-2-1-1, parameter
i-factor ).