KGL Operating Manual – VS 3010 BS
2018-07-02
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4.2 System Configuration
The VS 3010 BS pack controller has two low-pressure control loops (LP, compressor control) and a high-
pressure control loop (HP, condenser control). Two different temperature zones Z1 and Z2 are provided for the
compressor control; see also chapter 2 Functions. The Z1 temperature zone is operated in the NT range and
Z2 in the LT range as default. However, it is also possible to operate Z2 in the LT range so that the controller
can regulate two LT circuits; see chapter
.
System expansion options, page 20
The compressor controller basically includes the following control and regulation functions:
Low-pressure control (LP, compressor control) for one-circuit systems - as step or combined control
Low-pressure control (LP, compressor control) for one-circuit systems for the normal temperature (NT)
and low temperature (LT) temperature ranges - as step or combined control
Load shedding
Base load rotation
Compressor monitoring
Safety loop
Discharge gas defrosting D2D two-pipe system
High-pressure control (HP, condenser control) for one-circuit systems − as step, speed or combined control
4.2.1 System expansion options
The VS 3010 BS pack controller is specially designed for booster, satellite and cascade operation. In these
operating modes, different refrigeration circuits are operated with only one condenser unit and with only one
common high-pressure line. The refrigeration points are supplied from one common condenser receiver. The
following illustrations show the schematic layout.
Booster mode
During booster operation (parameter Boost./Kaskade = ON, see menu 3-1), the refrigeration points are also
supplied using the same liquid line. While the suction lines of the Z1 / NT circuit feed directly into the main
compressor, the refrigerant for the Z2 / frozen food display cases is initially fed through the so-called booster
stage. In the booster stage, the refrigerant pressure from the frozen food display cases, which is also lower
due to the lower evaporation temperature, is increased to the pressure level of the suction lines of the Z1
normal temperature refrigeration points.
If all the Z1 compressors are at standstill and Z2 compressors are loaded, the first Z1 compressor is loaded
immediately following the overshoot of the setpoint plus half of the neutral zone, i.e. the control times are
ignored. The control times remain ignored for the first compressor. Every additional Z1 compressor is loaded
after expiry of the basic and the variable lead time. If the suction pressure drops in the Z1 area, Z1
compressors are unloaded after expiry of the basic and variable unload time. One compressor remains in
operation, independent of the suction gas pressure. The Z1 compressor still being controlled is not switched
off until after all Z2 compressors have been switched off.
Layout of a booster system:
