ABB ACS550 Series, User Manual

Page: 185 / 310

ACS550 User’s Manual 185
Parameters
8121 REG BYPASS CTRL
Selects Regulator by-pass control. When enabled, Regulator by-pass control provides a simple control mechanism
without a PID regulator.
• Use Regulator by-pass control only in special
applications.
0 =
NO
– Disables Regulator by-pass control. The drive
uses the normal PFC reference: 1106
REF
2
SELECT
.
1 =
YES
– Enables Regulator by-pass control.
• The process PID regulator is bypassed.
Actual value of PID is used as the PFC reference
(input). Normally
EXT REF
2 is used as the PFC
reference.
• The drive uses the feedback signal defined by 4014
FBK SEL
(or 4114) for the PFC frequency reference.
• The figure shows the relation between the control
signal 4014
FBK SEL
(
OR
4114) and the speed
regulated motor’s frequency in a three-motor
system.
Example: In the diagram below, the pumping station’s
outlet flow is controlled by the measured inlet flow (A).
8122 PFC START DELAY
Sets the start delay for speed regulated motors in the system. Using the delay, the drive works as follows:
• Switches on the contactor of the speed regulated motor – connecting the motor to the ACS550 power output.
• Delays motor start for the time 8122
PFC START DELAY
.
• Starts the speed regulated motor.
• Starts auxiliary motors. See parameter 8115 for delay.
WARNING! Motors equipped with star-delta starters require a PFC Start Delay.
• After the ACS550 relay output switches a motor on, the star-delta starter must switch to the star-connection and
then back to the delta-connection before the drive applies power.
• So, the PFC Start Delay must be longer than the time setting of the star-delta starter.
8123 PFC ENABLE
Selects PFC control. When enabled, PFC control:
• Switches in, or out, auxiliary constant speed motors as output demand increases or decreases. Parameters 8109
START FREQ
1 to 8114
LOW FREQ
3 define the switch points in terms of the drive output frequency.
• Adjusts the speed regulated motor output down, as auxiliary motors are added, and adjusts the speed regulated
motor output up, as auxiliary motors are taken off line.
• Provides Interlock functions, if enabled.
• Requires 9904
MOTOR CTRL MODE
= 3 (
SCALAR
:
FREQ
).
0 =
NOT SEL
– Disables PFC control.
1 =
ACTIVE
– Enables PFC control.
Code Description
P 4014
P 8110
P 8109
P 8113
P 8112
A = No auxiliary motors running
B = One auxiliary motor running
C = Two auxiliary motors running
A B C (%)
f
OUT
f
MIN
f
MAX
M
3~
M
3~
M
3~
Outlet pipe3
Outlet pipe2
Outlet pipe1
P1
P2
P3
Sewage
tank
Contactors
P1
P2
P3
Mains 3~
3
3
3
3
ACS550
3
3
Inlet pipe
A