Danfoss ADAP-KOOL AKD 102 Operating Instructions Manual page 77

How to Programme the Frequ...
25-00 Pack Controller
Option: Function:
For operation of multiple devices (compressor)
systems where capacity is adapted to actual load
by means of speed control combined with on/off
control of the devices. For simplicity only
compressor systems are described.
[0] Disabled The Pack Controller is not active. All built-in
*
relays assigned to compressor motors in the Pack
function will be de-energized. If a variable speed
compressor is connected to the frequency
converter directly (not controlled by a built-in
relay), this compressor will be controlled as a
single compressor system.
[1] Enabled The Pack Controller is active and will stage/
destage compressors according to load on the
system.
NOTE
This parameter can only be Enabled [1], if parameter 28-00
Short Cycle Protection is set to Disabled [0].
25-06 Number of Compressors
Option: Function:
The number of compressors connected to
the Pack Controller including the variable
speed compressor. If the variable speed
compressor is connected directly to the
frequency converter and the other fixed
speed compressors (lag compressors) are
controlled by the two built in relays, three
compressors can be controlled. If both the
variable speed and fixed speed compressors
are to be controlled by built-in relays, only
two compressors can be connected.
[0] 2 If Fixed Lead Compressor, par. 25-05, is set to
compressors No [0]: one variable speed compressor and
*
one fixed speed compressor; both
controlled by built in relay. If Fixed Lead
Compressor, par. 25-05, is set to Yes [1]: one
variable speed compressor and one fixed
speed compressor controlled by built-in
relay
[1] 3 3 Compressors [1]: One lead compressor, see
compressors Fixed Lead Compressor, par. 25-05. Two fixed
speed compressors controlled by built-in
relays.
25-20 25-20 Neutral Zone [unit]
Range: Function:
4.00 [0-9999.99] Set the neutral zone (NZ) to accommodate
*
normal system pressure fluctuations. In pack
control systems, to avoid frequent switching
of fixed speed compressors, the desired
system pressure is typically kept within a
zone rather than at a constant level.
®
ADAP-KOOL Drive Operating Instructions
25-20 25-20 Neutral Zone [unit]
Range:
25-21 +Zone [unit]
Range:
3.00
*
[0-9999.99]
25-22 -Zone [unit]
Range:
3.00
*
[0-9999.99]
®
MG.11.L4.02 - ADAP-KOOL Drive
Function:
The NZ is programmed in the same unit as
selected in par. 20-12 Reference/Feedback
Unit.. It places a zone above and below the
set-point in which staging and destaging will
not occur. For example, if the set-point is -
20˚C and the NZ is set to 4˚C, a suction
pressure equivalent to a temperature
between - 24˚C and - 16˚C is tolerated. No
staging or destaging will occur within this
zone.
Function:
When a large and quick change in the system
demand occurs, the system pressure rapidly
changes and a quicker staging or destaging
of a fixed speed compressor becomes
necessary to match the requirement. The
+Zone defines the range where the + zone
delay is active.
Setting the +Zone too close to zero could
defeat the purpose with frequent staging at
momentary pressure changes. Setting the
+Zone too high might lead to an
unacceptably high or low pressure in the
system while the +Zone Delay timer (par.
25-24) is running. The +Zone value can be
optimized with increased familiarity with the
system. See ++Zone Delay, par. 25-26.
To avoid unintended staging during the
commissioning phase and fine tuning of the
controller, initially set the +Zone to a large
value beyond any expected pressure peak.
This implicitly disables the override function
for pressure peaks. When the fine tuning is
complete, the +Zone should be set to the
desired value. An initial value of 3˚C is
suggested.
Function:
When a large and quick change in the
system demand occurs, the system pressure
rapidly changes and a quicker staging or
destaging of a fixed speed compressor
becomes necessary to match the
requirement. The -Zone defines the range
where the - zone delay is active.
Setting the -Zone too close to zero could
defeat the purpose with frequent staging at
momentary pressure changes. Setting the -
Zone too high might lead to an unacceptably
high or low pressure in the system while the
-Zone Delay timer (par. 25-25) is running. The
-Zone value can be optimized with increased
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