ACS 400 User’s Manual 119
Group 81: PFC Control
Parameters for Pump-Fan Control (PFC). “Appendix B” on page 157 gives detailed information on
PFC. “Application Macros” on page 53 describes the default signal connections.
Code Description
8103 REFERENCE STEP 1
Sets a percentage value that is added to the process reference when at least one
auxiliary (constant speed)
motor is running. Default value is 0 %.
Example: An ACS 400 operates three parallel pumps that pump water to a pipe. The pressure in the pipe is
controlled. The constant pressure reference is set by parameter 4020
INTERNAL SETPNT.
At low water consumption levels, only the speed regulated pump is run. When water consumption
increases, constant speed pumps are started; first one pump, and, if the demand is still growing, the other
pump.
When water flow increases, the pressure loss increases between the beginning (measurement site) and the
end of the pipe. By setting suitable reference steps (parameters 8103
REFERENCE STEP1 and 8104
REFERENCE STEP2) the process reference is increased along with the increasing pumping capacity. The
reference steps compensate the growing pressure loss and prevent the pressure drop at the end of the
pipe.
8104 REFERENCE STEP 2
Sets a percentage value that is added to the process reference when at least two
auxiliary (constant speed)
motors are running. Default value is 0 %. See parameter 8103
REFERENCE STEP1
8105 REFERENCE STEP 3
Sets a percentage value that is added to the process reference when at least three
auxiliary (constant
speed) motors are running. Default value is 0 %. See parameter 8103
REFERENCE STEP1.
8109 START FREQ 1
Sets a frequency limit. See Figure 50 on page 120. When ACS 400 output frequency exceeds value (8109
START FREQ 1 + 1 Hz) and no auxiliary motors are running, the Start Delay counter is started. When the time
set with parameter 8115
AUX MOT START D is elapsed and if the output frequency is still above value (8109
START FREQ 1 - 1 Hz), the first auxiliary motor is started.
After the first auxiliary motor is started, ACS 400 output frequency is decreased by value (8109
START
FREQ 1 - 8112 LOW FREQ 1).
Note! Start Frequency 1 should be within limits 8112
LOW FREQ 1 and 2008 MAXIMUM FREQ -1.
8110 START FREQ 2
Sets a frequency limit (see Figure 50). When the ACS 400 output frequency exceeds value (8110
START
FREQ 2 + 1 Hz) and one auxiliary motor is running, the Start Delay counter is started. When the time set with
parameter 8115
AUX MOT START D is elapsed and if the output frequency is still above value (8110 START
FREQ 2 - 1 Hz), the second auxiliary motor is started.
After the second auxiliary motor is started, the ACS 400 output frequency is decreased by value (8110
START FREQ 2 - 8113 LOW FREQ 2).
Note! Start Frequency 2 should be within limits 8112
LOW FREQ 2 and 2008 MAXIMUM FREQ -1.
8111 START FREQ 3
Sets a frequency limit (see Figure 50). When the ACS 400 output frequency exceeds the value (8111
START
FREQ 3 + 1 Hz) and two auxiliary motors are running, the Start Delay counter is started. When the time set
with parameter 8115
AUX MOT START D is elapsed and if the output frequency is still above value (8111 START
FREQ 3 - 1 Hz), the third auxiliary motor is started.
After the third auxiliary motor is started, the ACS 400 output frequency is decreased by value (8111
START
FREQ 3 - 8114 LOW FREQ 3).
Note! Start Frequency 3 should be within limits 8112
LOW FREQ 3 and 2008 MAXIMUM FREQ -1.
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