ECKELMANN VS 300 - Control Algorithm for High-Pressure Control

Function of VS 300
48
Doku-Version 2.05 - Firmware 2.10 - 15. September 2017
4.5.3 Control algorithm for high-pressure control
The controller cycle time is 1 second. The control algorithm varies with the control type.
In the wet vapor range, temperature is a distinct function of refrigerant and pressure:
t = f (p, refrigerant). The VS 300 makes calculation from the pressures measured as a function
of the given refrigerant temperatures. Exclusively temperature values are used for control.
Temperatures (t
0
, t
c
) listed in the documentation therefore substitute for pressures (p
0
, p
c
).
4.5.4 Control algorithm with step controller
High pressure detected by an A/D converter is compared with the setpoint (see section 4.5.10 Determining the
High-pressure Setpoint). The following relationship applies:
Controlerror 
With a positive control error (t
c_Act
> t
c_Setp
+ 0.5 x Neutral Zone) and rising pressure, the step controller moves
forward one step. This means that one additional condenser capacity stage is enabled. With a positive control
error and falling pressure, no capacity stage is loaded in anticipation of pressure reaching the neutral zone in a
short time.
With a negative control error (t
c_Act
> t
c_Setp
- 0.5 x Neutral Zone) and falling pressure, the step controller
moves back one step. This means that one additional condenser capacity stage is disabled. With a negative
control error and rising pressure, no capacity stage is unloaded in anticipation of pressure reaching the neutral
zone in a short time.
C1
Time
ZNR. 51203
65 030 E1
Starts monitoring
C2
C3
Start time delay =6Min.
Off time
Start time delay =6Min.
Off time
Start time delay =6Min. No off time