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ACH550-UH User’s Manual
1-175
Parameters
8117
NR OF AUX MOT
0…4
1
1
Sets the number of auxiliary motors.
• Each auxiliary motor requires a relay output, which the drive uses to send start/stop signals.
• The Autochange function, if used, requires an additional relay output for the speed regulated motor.
• The following describes the set-up of the required relay outputs.
Relay outputs
As noted above, each auxiliary motor requires a relay output, which the drive uses to send start/stop signals. The
following describes how the drive keeps track of motors and relays.
• The ACH550 provides relay outputs RO1…RO3.
• An external digital output module (OREL-01) can be added to provide relay outputs RO4…RO6.
• Parameters 1401…1403 and 1410…1412 define, respectively, how relays RO1…RO6 are used – the parameter
value 31
PFA
defines the relay as used for PFA.
• The ACH550 assigns auxiliary motors to relays in ascending order. If the Autochange function is disabled, the first
auxiliary motor is the one connected to the first relay with a parameter setting = 31
PFA
, and so on. If the
Autochange function is used, the assignments rotate. Initially, the speed regulated motor is the one connected to
the first relay with a parameter setting = 31
PFA
, the first auxiliary motor is the one connected to the second relay
with a parameter setting = 31
PFA
, and so on.
• The fourth auxiliary motor uses the same reference step, low frequency and start frequency values as the third
auxiliary motor.
Group 81: PFA Control
Code Description Range
Resolution
Default
S
ACH550
Standard PFA mode
PFA with Autochange mode
ACH550
Relay logic
Summary of Contents for ACH550-UH HVAC
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Page 8: ...1 8 ACH550 UH User s Manual Table of contents ...
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