Chapter 6 – Parameters
6-46 ACH 500 Programming Manual
The Pump and Fan Control (PFC) is a special type of PI-Control that will
allow the ACH 500 to sequence on additional or lag motors when the demand
exceeds the capabilities of one motor. As in the HVAC-PI macro, the ACH
500 is given two signals: a setpoint (or reference) and a feedback (or actual).
The output frequency of the ACH 500 will adjust automatically to maintain
the feedback at the same value as the setpoint. If the feedback and setpoint are
not equal, the output frequency will increase or decrease.
An additional feature of the PFC is that if the output frequency reaches a high
limit without making the feedback equal to the setpoint, a second motor will
be started and the output frequency of the drive will decrease. Up to three lag
motors can be connected.
An example of Pump and Fan Control use is provided after the following
description of the parameters.
21 ERROR VALUE
INVERT
NO/YES PI-Controller error value
inversion.
22 ACTUAL 1 INPUT (O) NO/AI1/AI2 Actual 1 signal input selection.
23 ACTUAL 2 INPUT (O) NO/AI1/AI2 Actual 2 signal input selection.
24 ACTUAL VALUE
SEL (O)
ACT1/ACT1 - ACT2/
ACT+ACT2/
ACT1*ACT2/
min(A1,A2)/
max(A1,A2)/sqrt(ACT1)/
sqA1+sqA2
PI-Controller output signal
selection.
25 ACT 1 MIN SCALE -1600.0 – +1600.0% Minimum scaling factor of the
Actual 1.
26 ACT 1 MAX SCALE -1600.0 – +1600.0% Maximum scaling factor of the
Actual 1.
27 ACT 2 MIN SCALE -1600.0 – +1600.0% Minimum scaling factor of the
Actual 2.
28 ACT 2 MAX SCALE -1600.0 – +1600.0% Maximum scaling factor of the
Actual 2.
29 REGUL. BYPASS OFF/ON Bypass PI Regulator.
30 DISPLAY UNIT NO UNIT; bar; %; m/s;
C; F; diff temp; kPa;
1/min; m
3
/min; gpm; psi;
dpsi; cFm; ft; in.; inHg
Units of ACT1 and ACT2 on
the display.
31 DISPL UNIT SCALE 0 – 50000 Scaling factor for display.
32 NBR OF DECIMALS 0 – 5 Number of decimal digits.
Parameter Range/Unit Description
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