Danfoss VLT Refrigeration Drive FC 103 Programming Manual page 173

Parameter Description
3.20.2 25-0* System Settings
Parameters related to control principles and configuration
of the system.
25-00 Pack Controller
Option: Function:
For operation of multiple device systems where
capacity is adapted to actual load with 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 are de-energized. If a variable speed
compressor is connected to the frequency
converter directly (not controlled by a built-in
relay), this compressor is controlled as a single-
compressor system.
[1] Enabled The pack controller is active and stages/destages
compressors according to load on the system.
NOTICE
This parameter can only be [1] Enabled, if
parameter 22-75 Short Cycle Protection is set to [0]
Disabled.
25-02 Motor Start
Option: Function:
Motors are connected to mains directly with a
contactor or with a soft starter. When the value of
parameter 25-02 Motor Start is set to an option
other than [0] Direct on Line, then
parameter 25-50 Lead Pump Alternation is automat-
ically set to the default of [0] Direct on Line.
[0] Direct Each fixed speed pump is connected to mains
on Line directly via a contactor.
*
[1] Soft Each fixed speed pump is connected to mains via
Starter a soft starter.
[2] Star- Fixed pumps connected with star-delta starters
Delta are staged in the same way as pumps connected
with soft starters. They are destaged in the same
way as pumps connected directly to mains.
25-04 Pump Cycling
Option: Function:
To provide equal hours of operation with fixed
speed compressors, the compressor used can be
cycled. The selection of compressor cycling is
either first in – last out or equal running hours for
each compressor.
[0] Disabled The fixed speed compressors are connected in
*
the order 1–2 and disconnected in the order 2–1
(first in–last out).
MG16H202
Programming Guide
25-04 Pump Cycling
Option:
[1] Enabled The fixed speed compressors are connected/
25-05 Fixed Lead Compressor
Option: Function:
[0] No
[1] Yes The lead compressor is fixed (no alternation) and
*
25-06 Number of Compressors
Range:
2 [ 2
*
- 6]
Danfoss A/S © 05/2016 All rights reserved.
Function:
disconnected to have equal running hours for
each compressor.
Fixed lead compressor is a configuration when the
variable speed compressor is connected directly to the
frequency converter, and if a contactor is applied
between frequency converter and compressor, this
contactor is not controlled by the frequency converter.
If operating with parameter 25-50 Lead Pump
Alternation set to other than [0] Off, set this parameter
to [0] No.
The lead compressor function can alternate between
the compressors controlled by the 2 built-in relays.
Connect 1 compressor to the built-in relay 1, and the
other compressor to relay 2. The compressor function
(pack compressor1 and pack compressor2) is automat-
ically assigned to the relays (maximum 2 compressors
can in this case be controlled by the frequency
converter).
connected directly to the frequency converter. The
parameter 25-50 Lead Pump Alternation is automatically
set to [0] Off. Built-in relays relay 1 and relay 2 can be
assigned to separate fixed speed compressors. In total,
3 compressors can be controlled by the frequency
converter.
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 2
built-in relays, 3 compressors can be controlled. If both
the variable speed and fixed speed compressors are
controlled by built-in relays, only 2 compressors can be
connected.
If parameter 25-06 Number of Compressors is set to 2
compressors, the set-up is: 1 variable speed
compressor and 1 fixed speed compressor, both
controlled by built-in relay.
If parameter 25-06 Number of Compressors is set to 3
compressors, the set-up is: 1 variable speed
compressor and 2 fixed speed compressors, all
controlled by the built-in relay. Up to 6 compressor can
®
be controlled using the VLT Extended Relay Card MCB
113.
3 3
171