Instruction manual

Cascade Controller Option
there are three types of output signals: 0 to 20 mA, 4
to 20 mA, or 0 to 32000 pulses. The pulse rate is set
by parameter 320, Terminal 42, O utput, Pulse Scaling.
Description of choice:
Set the output of terminal 42 to Output Frequency
(pulse sequence), (OUT.FREQ.PULSE) for Master/Slave
operation as shown in the wiring diagram in Chapter
4. Using frequency pulse is a reliable way of providing
the same speed reference to all slave drives. Current
output is limited to two slave drives.
System pressure and flow requirements can often be
generated using parallel pumps at different efficiencies.
The cascade controller can automatically configure
the number of pumps in operation to achieve the
highest system efficiency. Running three pumps at full
speed, for example, may satisfy system requirements,
while running four pumps at a lower speed meets
requirements and achieves higher efficiency.
Danfoss has available the Multiple Unit Staging
Efficiency Calculator (MUSEC), a free software
program available on the Danfoss website. By
entering pump and system data, MUSEC provides
the programmer with on and off staging frequencies
for each pump at optimal efficiency. Enter the data
for each pump in Extended Menu parameters 739
and 740. For a free download, go to www.dan-
foss.com/BusinessAreas/DriveSolutions/Software
download/PS software download.
Quick Menu 034 Par. 739 Master/Slave
staging on frequencies
(M/S STAGE FREQ)
Value:
Min. freq - Max. freq
(Par. 201 - 202)
✭ Min. freq.
Function:
Best efficiency staging on frequency can be calculated
for the cascade controller based on pump and system
curves to meet feedback requirements. Use the
MUSEC software program to determine the most
efficient staging on frequency for each pump.
Description of choice:
Enter the staging on frequency for each pump.
After pressing the CHANGE DATA key in parameter
739, use the (+) and (-) keys to scroll through
all four slave settings.
If the pump or system data is unknown, refer
to the section Alternative Programming at
the end of this chapter.
Quick Menu 035 Par. 740 Master/Slave
staging off frequencies
(M/S DESTAGE FREQ)
Value:
Min. freq - Max. freq
(Par. 201 - 202)
✭ Min. freq.
Function:
Best efficiency staging off frequency can be calculated
for the cascade controller based on pump and system
curves to meet feedback requirements. Use the
MUSEC software program to determine the most
efficient staging off frequency for each pump.
Description of choice:
Enter the staging off frequency for each pump.
After pressing the CHANGE DATA key in parameter
740, use the (+) and (-) keys to scroll through
all four slave settings.
If the pump or system data is unknown, refer
to the section Alternative Programming at
the end of this chapter.
Quick Menu 040 Par. 420 PID normal/inverse
control
(PID NOR/INV. CTRL)
Value:
✭Normal (NORMAL)
[0]
Inverse (INVERSE)
[1]
Function:
This determines how the drive’s PID controller
responds to a difference between the setpoint and
feedback. Normal is when the drive is to reduce the
output frequency as the feedback signal increases
.
Inverse is when the drive is to increase the output
frequency as the feedback signal increases.
MG.60.I5.22 - VLT is a registered Danfoss trademark
53
Master/Slave Cascade
Control Setup