ECKELMANN VS 300 - 4.4 Monitoring Functions

Function of VS 300
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Doku-Version 2.05 - Firmware 2.10 - 15. September 2017
4.3.22 Load shedding
Forced shutdown of a refrigeration point may be necessary to prevent exceeding a defined energy consumption
level. Load shedding can be called via a digital input on the VS 300 Pack Controller (see section 7 Parameter
List and Menu Structure – Common Setpoints).
The number of stages to be disabled on load shedding can be defined for each control loop. Unloading of com
pressors takes place directly. A minimum refrigeration capacity must be maintained regardless of receipt of a
load shedding signal, meaning that a minimum number of compressors must be enabled.
A minimum of one compressor is enabled at all times. A single-compressor system cannot be disabled by load
shedding.
4.3.23 Base load rotation
Run time of each compressor is internally monitored. So as to achieve even run time of all compressors, the
compressor having the longest run time at the end of a definable cycle time is disabled and that having the
shortest run time is enabled.
Base load rotation is performed only with the step controller or combined controller control types. With capacity-
controlled compressors, base load rotation takes place only when the base load stage of a compressor is avail
able. Base load rotation consists of all stages (base load and any capacity stages) of the compressor having the
longest run time being disabled and the base load stage having the shortest run time being loaded. Actuation
state of any capacity stages is transferred to the capacity stages of the new base load stage. In base load rota
tion allowance is made for the number of capacity stages controlled on a compressor.
When operating capacity-controlled compressors and non-capacity-controlled compressors together,
base load rotation can only be performed among a multiple number of capacity-controlled compres
sors or a multiple number of non-capacity-controlled compressors.
Compressors disabled by load shedding are taken into account during base load rotation. The number of run
ning compressors is not changed on base load rotation. Especially with screw compressors, which have an oil
return system and do not require base load rotation, the parameter for Base Load Rotation Cycle Time can be
set to ”--”, thus deactivating base load rotation.
4.4 Monitoring functions
Monitoring functions as follows are integrated in the controller as well as control and regulating functions:
S High pressure
S Low pressure
S Compressor starts
S Monitoring of the digital inputs (fast unload, load shedding, second setpoint, external alarm, heat recovery
mode, safety loop, see section 4.2 Configuring/Monitoring digital inputs).