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Control action of the example system
In the following description, the control action of the system is shown using the example of the above named
system. The configured frequency range is thus 35 Hz - 67 Hz; the configured capacity overlap is 10%. It can
be specified using the output overlap parameter by how many percent (100% corresponds to the capacity of a
completely loaded compressor at 50 Hz) the capacity after loading a compressor stage is lower than before the
loading.
Parametrisation and connection of the system
Connection: the single-stage FC compressor is enabled using the compressor relay stage 1 (terminals 13/14)
of the pack controller. Depending on the number of selected capacity stages (parameter
Nr comp multist
menu
3-1), one or two additional capacity stages are reserved for the FC compressor:
•
If the number of selected capacity stages in the circuit is equal to two, the second relay stage (terminals
23/24) is assigned to the FC compressor.
•
If the number of selected capacity stages in the circuit is equal to three, the second and third relay
stages (terminals 23/24 and terminals 33/34) are assigned to the FC compressor.
These capacity stages that are assigned to the FC compressor are disabled for the operation with a single-
stage FC compressor using the manual control switch(es) and the corresponding parameters (menu 3-1).
Nothing is connected to the corresponding relay stages.
The capacity-controlled fixed-speed compressors are connected to the compressor relay stages (see above
diagram of the example system).
Parameters:
The following settings must be made in the System Configuration menu (menu 3-1) for the
example configuration described above:
No. comps.
= 4 Number of compressors in the pack
No.cap.stages
= 2 Number of capacity stages per compressor in the pack
In the submenu
Enable comp.stages
, the capacity stages assigned to the FC compressor must be disabled
using the parameters
Comp. 2
(two-stage compressor) or
Comp.
2
and
Comp.
3
(three-stage compressor).
The following settings must be made for the example configuration described above in the Compressor Control
menu (menu 3)
Setpoints
/ 2
Control
/ 1
LP Control
/ 1
Compressor Control
):
•
Regelungsart
=
combined control
to-control combined with FC compressor and fixed-speed compressors
•
Diff.Power
= 10%
Capacity overlap when loading or unloading a compressor capacity stage. The capacity overlap
determines which speed setpoint for the FC compressor is output following the loading / unloading of a
compressor capacity stage.
•
M.com.out.reg.
= YES
This is used to specify that the stages of the fixed-speed compressors are switched on individually when
using compressor combined control (capacity control of the fixed-speed compressors is active).
NO in this case means that the fixed-speed compressors together with their capacity stages are always
loaded and unloaded completely (capacity control of the fixed-speed compressors is inactive).
•
MaxFreq.FC[Hz]
= 87
The frequency to be output by the FC for 10 V correcting variable is set here (setting value must
correspond to the value set on the FC; the example here uses 87 Hz).
•
MinFreq.FC[Hz]
= 30
The frequency to be output by the FC for 0 V correcting variable is set here (setting value must
correspond to the value set on the FC; the example here uses 30 Hz).
•
U.WorkFreq[Hz]
= 67
Upper operating frequency: The maximum FC speed output by the controller is set here. This must be
selected to be less than or equal to the maximum frequency to be output by the FC.
•
L.WorkFreq[Hz]
= 35
Lower operating frequency: The minimum FC speed output by the controller is set here. This must be
selected to be greater than or equal to the minimum frequency to be output by the FC..
Summary of Contents for VS 3015 C
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