GE Ecomagination AF-600 FP Programming Manual page 179

Parameter Description
3 3
Illustration 3.69 Destaging
NOTICE
Fixed pumps connected with star-delta starters 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.
PC-42 Staging Threshold
Range:
90 [0 -
% 100 %]
*
178
Function:
When adding a fixed speed pump to prevent an
overshoot of pressure, the variable speed pump
ramps down to a lower speed. When the variable
speed pump reaches the staging speed the fixed
speed pump is staged on. The staging threshold is
used to calculate the speed of the variable speed
pump when the cut-in point of the fixed speed
pump occurs. The calculation of the staging
threshold is the ratio of parameter F-18 Motor
Speed Low Limit [RPM] or parameter F-16 Motor
Speed Low Limit [Hz], to the parameter F-17 Motor
Speed High Limit [RPM] or parameter F-15 Motor
Speed High Limit [Hz], expressed in percent.
Staging threshold must range from
LOW
= × 100 %
STAGE %
HIGH
to 100%, where n is motor speed low limit and
LOW
n is Motor Speed High Limit.
HIGH
Illustration 3.70 Staging Threshold
NOTICE
If the setpoint is reached after staging before the
variable speed pump reaches its minimum speed - the
system enters the state closed loop as soon as the
feedback pressure is crossing the set-point.
PC-43 Destaging Threshold
Range:
50 [0 -
% 100 %]
*
Illustration 3.71 Destaging Threshold
03/2016 All rights reserved.
Function:
When removing a fixed speed pump to prevent an
undershoot of pressure, the variable speed pump
ramps up to a higher speed. When the variable
speed pump reaches the destaging speed, the
fixed speed pump is destaged. The destaging
threshold is used to calculate the speed of the
variable speed pump when the destaging of the
fixed speed pump occurs. The calculation of the
destaging threshold is the ratio of
parameter F-18 Motor Speed Low Limit [RPM] or
parameter F-16 Motor Speed Low Limit [Hz], to
parameter F-17 Motor Speed High Limit [RPM] or
parameter F-15 Motor Speed High Limit [Hz],
expressed in percent.
Destaging threshold must range from
LOW
STAGE % = × 100 % to 100%, where n
HIGH
speed low limit and n is motor speed high
HIGH
limit.
is motor
LOW
DET-620D