activated, an alternation is carried out by ramping the
variable speed compressor to
4-13 Motor Speed High Limit
[RPM]
or
4-14 Motor Speed High Limit [Hz]
, and then
decelerated to zero speed. After a “Delay Before Starting
Next Compressor” (
25-58 Run Next Compressor Delay
) the
next lead compressor (middle graph) is accelerated and
another original lead compressor (top graph) is added after
the “Delay Before Running On Mains” (
25-59 Run on Mains
Delay
) as a fixed speed compressor. The next lead
compressor (middle graph) is decelerated to Motor Speed
Low Limit and then allowed to vary speed to maintain
system pressure.
Illustration 6.37
25-58 Run Next Compressor Delay
Range:
Function:
0.5
sec
*
[
25-58 Run
Next Compressor
Delay
– 5.0 sec]
This parameter is only active if the
option selected in
25-50 Lead
Compressor Alternation
, is different
from
[0] Off
.
This parameter sets the time between
stopping the old variable speed
compressor and starting another
compressor as a new variable speed
compressor. Refer to
25-56 Staging
Mode at Alternation
and
for description of staging and
alternation.
25-59 Run on Mains Delay
Range:
Function:
0.5
sec
*
[
25-58 Run
Next Compressor
Delay
– 5.0 sec ]
This parameter is only active if the
option selected in
25-50 Lead
Compressor Alternation
, is different
from
[0] Off
.
This parameter sets the time between
stopping the old variable speed
compressor and starting this
compressor as a new fixed speed
compressor. Refer to
25-56 Staging
Mode at Alternation
and
for description of staging and
alternation.
6.14.5 25-8* Status
Readout parameters informing about the operating status
of the cascade controller and the compressors controlled.
25-80 Pack Status
Option:
Function:
Read out of the status of the Pack Controller.
Disabled
Pack Controller is disabled (
25-00 Cascade
Controller
).
Emergency
All compressors have been stopped by means
of a Coast/Coast inverse or an External Interlock
command applied to the frequency converter.
Off
All compressors have been stopped by means
of a Stop command applied to the frequency
converter.
In Open Loop
1-00 Configuration Mode
has been set for
[0]
Open Loop
. All fixed speed compressors are
stopped. The variable speed compressor will
continue to run.
Frozen
Staging/destaging of compressors has been
locked and reference locked.
Jogging
All fixed speed compressors are stopped. When
stopped, the variable speed compressor will run
at jog speed.
Running
A Start command is applied to the frequency
converter and the Pack controller is controlling
the compressors.
Running FSBW The frequency converter is tripped off and the
Pack Controller is controlling the fixed speed
compressors based on
4-14 Motor Speed High
Limit [Hz]
.
Staging
The Pack Controller is staging fixed speed
compressors.
Destaging
The Pack Controller is destaging fixed speed
compressors.
Lead Not Set
No compressor available to be assigned as
variable speed compressor.
Parameter Descriptions
Operating Instructions VLT
®
CDS302 and CDS303
MG34M302 - VLT
®
is a registered Danfoss trademark/Commercial Compressor
115
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