Version 2.02 15.05.2007 Function of VS 3000
6
3.2.1 Setting parameters for LP transducer characteristic
The VS 3000 Pack Controller works with linear-characteristic continuous pressure transducers. The pressure in-
puts can be matched to various transducers with linear characteristic. Transducers with either current output (4 to
20 mA) or voltage output (0 to 10 V) may be used.
Jumpers must be changed accordingly on the controller for voltage-output transducers!
The default configuration is for current inputs!
The following parameters (Menu 3-1-a) are used to match the controller to the transducer:
1.LP-Transducer
- The LP transducer must be selected for either continuous current output 4 to 20 mA or
continuous voltage output 0 to 10 V.
2.LP-Min
- This parameter defines the pressure p
0
at which the transducer delivers a 4 mA or 0 V output signal.
3.LP-Max
- The parameter defines the pressure p
0
at which the transducer delivers a 20 mA or 10 V output signal.
Changing any of these parameters causes a Sensor Type Change message to be generated.
Incorrect parameter setting can result in severely impaired function.
3.2.2 Neutral zone
If low-pressure control is made by step controller, no compressor actuation takes place as long as the control
error remains within a definable neutral zone. If low-pressure control is made by combined controller, the im-
plications of the neutral zone are as follows:
If control error is within the range of 1.5 times the neutral zone, low pressure is controlled by increasing or de-
creasing compressor speed. Outside the range of 1.5 times the neutral zone, the variable-speed compressor
runs at either maximum or minimum speed to achieve quick control correction.
3.2.3 Control algorithm
Controller cycle time is 1 second. The control algorithm depends on the type of control.
In the wet vapor range the temperature is clearly governed by the refrigerant and pressure:
t = f (p, refrigerant).The VS 3000 calculates temperatures from the pressures measured as a function
of the refrigerant used. Exclusively temperature measurements are used for control.
In this manual therefore, temperatures (t
0
,t
c
) stand for pressure (p
0
,pc).
To Next Page
Loading...
Need help?
General
