Danfoss VLT FC 102 Programming Manual page 567

Programming Guide | VLT® HVAC Drive FC 102
The following illustration is an example of the slow transfer-staging. The variable-speed pump (top graph) and 1 fixed-speed pump
(bottom graph) run before the staging command. When the [0] Slow transfer command is activated, an alternation is carried out by
ramping the variable-speed pump to parameter 4-13 Motor Speed High Limit [RPM] or parameter 4-14 Motor Speed High Limit [Hz], and
then decelerated to zero speed. After a delay before starting the next pump (parameter 25-58 Run Next Pump Delay), the next lead pump
(middle graph) is accelerated and another original lead pump (top graph) is added after the delay before running on mains (parameter
25-59 Run on Mains Delay) as a fixed-speed pump. The next lead pump (middle graph) is decelerated to motor speed low limit and then
allowed to vary speed to maintain system pressure.
Motor speed
high limit
Destaging
speed
Motor speed
low limit
Staging
command
next pump
Motor speed
high limit
Staging
speed
Motor speed
low limit
Motor speed
high limit
Destaging
speed
Motor speed
low limit
Figure 111: Staging Mode at Alternation
Option Name
[0]* Slow
[1] Quick
[2] Slow down
25-58 Run Next Pump Delay
Default value: 0.1 s
Setup:
All setups
Data type: Uint16
This parameter is only active if the option selected in parameter 25-50 Lead Pump Alternation is different from [0] Off. This parameter
sets the time between stopping the old variable-speed pump and starting another pump as a new variable-speed pump. Refer to
parameter 25-56 Staging Mode at Alternation for a description of staging and alternation.
© 2024.10
Fixed-speed
Variable-speed
pump
pump
Delay before
running
on mains
Variable-speed
pump
Delay
before starting
Fixed-speed
pump
Seconds
Seconds
Seconds
Description
At alternation, the variable-speed pump is ramped up to
maximum speed and then ramped down to a standstill.
At alternation, the variable-speed pump is ramped up to
maximum speed and then coasted to a standstill.
At alternation, the variable-speed pump is ramped down to a
standstill.
Parmaeter type:
Conversion index:
Change during operation:
Parameter Descriptions
Range, 0.1 - 5 s
-1
True
AU430028034214en-001901 / 130R0310 | 567