Danfoss VLT Programming Manual page 170

Parameter Description
3.23.1 25-0* System Settings
Parameters related to control principles and configuration of
the system.
25-00 Cascade Controller
Option: Function:
For operation of multiple devices (pump/fan)
systems where capacity is adapted to actual load
by means of speed control combined with on/off
control of the devices. For simplicity only pump
systems are described.
[0] Disabled The Cascade Controller is not active. All built-in
*
relays assigned to pump motors in the cascade
function will be de-energized. If a variable speed
pump is connected to the frequency converter
directly (not controlled by a built-in relay); this
pump/fan will be controlled as a single pump
system.
[1] Enabled The Cascade Controller is active and will stage/
destage pumps according to load on the system.
25-02 Motor Start
Option: Function:
Motors are connected to the mains directly with
a contactor or with a soft starter. When the value
of 25-02 Motor Start is set to an option other than
Direct on Line [0], then 25-50 Lead Pump
Alternation is automatically set to the default of
Direct on Line [0].
[0] Direct on Each fixed speed pump is connected to line
*
Line directly via a contactor.
[1] Soft Each fixed speed pump is connected to line via a
Starter soft starter.
[2] Star-Delta
25-04 Pump Cycling
Option: Function:
To provide equal hours of operation with fixed
speed pumps, the pump use can be cycled. The
selection of pump cycling is either "first in – last
out" or equal running hours for each pump.
[0] Disabled The fixed speed pumps will be connected in the
*
order 1 – 2 and disconnected in the order 2 – 1.
(First in – last out).
[1] Enabled The fixed speed pumps will be connected/discon-
nected to have equal running hours for each
pump.
®
VLT HVAC Drive Programming Guide
25-05 Fixed Lead Pump
Option:
[0]
[1]
25-06 Number of Pumps
Range:
2
®
MG.11.CB.02 - VLT is a registered Danfoss trademark
Function:
Fixed Lead Pump means that the variable speed pump
is connected directly to the frequency converter and if a
contactor is applied between frequency converter and
pump, this contactor will not be controlled by the
frequency converter.
If operating with 25-50 Lead Pump Alternation set to
other than Off[0], this parameter must be set to No [0].
No The lead pump function can alternate between the
pumps controlled by the two built in relays. One pump
must be connected to the built-in RELAY 1, and the
other pump to RELAY 2. The pump function (Cascade
Pump1 and Cascade Pump2) will automatically be
assigned to the relays (maximum two pumps can in this
case be controlled from the frequency converter).
Yes The lead pump will be fixed (no alternation) and
*
connected directly to the frequency converter. The
25-50 Lead Pump Alternation is automatically set to Off
[0]. Built-in relays Relay 1 and Relay 2 can be assigned to
separate fixed speed pumps. In total three pumps can
be controlled by the frequency converter.
Function:
[2 - The number of pumps connected to the Cascade
*
9. ] Controller including the variable speed pump. If the
variable speed pump is connected directly to the
frequency converter and the other fixed speed pumps
(lag pumps) are controlled by the two built in relays,
three pumps can be controlled If both the variable
speed and fixed speed pumps are to be controlled by
built-in relays, only two pumps can be connected.
If 25-05 Fixed Lead Pump, is set to No [0]: one variable
speed pump and one fixed speed pump; both
controlled by built in relay. If 25-05 Fixed Lead Pump is
set to Yes [1]: one variable speed pump and one fixed
speed pump controlled by built-in relay.
One lead pump, see 25-05 Fixed Lead Pump. Two fixed
speed pumps controlled by built-in relays.
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