ABB ACH550-UH User Manual page 391

ACH550 E-Clipse Bypass User's Manual
Start/Stop (DI1)
The Start/Stop input is connected to a normally open contact that starts and stops
the system. When the bypass is in the Drive mode and the drive is in the Auto mode,
the Start/Stop input contact controls the motor by starting and stopping the drive.
When the bypass is in the Bypass mode and Auto is indicated on the bypass control
display, the Start/Stop input contact controls the motor by controlling the bypass
contactor.
Run Enable (DI2)
The Run Enable input is connected to the series combination of any external
normally closed permissive contacts, such as damper end switches, that must be
closed to allow the motor to run. If any of these external contacts are open while a
Start command is present, the Enabled LED will flash green and the motor is
prevented from running.
Reverse Drive (DI2)
The Reverse Drive input can be connected to an external contact that is closed to
select the Reverse Drive mode. See
description of this mode.
Safety Interlock (DI2...DI5)
The Safety Interlock input(s) are connected to the series combination of any external
normally closed interlock contacts, such as Firestat, Freezestat, and high static
pressure switches – switches that must be closed to allow the motor to run. If any of
these external contacts are open, the Enabled LED is illuminated red, the drive
output contactor, bypass contactor, and System Started relay are de-energized
preventing the motor from running.
Bypass Fault Reset (DI4)
The Bypass Fault Reset input can be connected to an external contact that is closed
to reset a bypass fault. It may take several minutes before the bypass can be reset
after an overload trip.
Advanced Override (DI5) (Override 2)
The Advanced Override (Override 2) input can be connected to an external contact
that is closed to select the Advanced Override mode. See
(Override 2)
Smoke Control (DI6) (Override 1)
The Smoke Control (Override 1) input can be connected to an external contact that
is closed to select the Fireman's Override mode. See
(Override 1)
on page for a description of this mode.
2-39
on page for a description of this mode.
2-38
on page
Reverse Drive Mode
Advanced Override Mode
Smoke Control Mode
2-45
for a
2-37
Bypass functions overview