A 24 volt, 14Ah
Battery Backup System
with a float charger is included that will
automatically open the door at design loads anytime power is interrupted. This assures that
the same level of safety is provided at all times in order to reduce the chance of personal
injury.
The
NB-4000
features the same
Absolute Position Feedback Control
system and
software as other
brookfield industries, inc
. door operators. There are no limit or
proximity switches to adjust or install for any of the door positions under normal
operation.
Simply adjust the door’s positioning presets as required by interfacing with the PLC via a
hand held Data Access Unit (purchased separately).
A
Rotary Position Transducer
attached to the worm gear output shaft provides the
position of the door. As the door changes position, the output signal from the transducer
varies in value. This signal, once converted to a digital value, is stored in the CPU for
further processing. This devise does not need to be “homed” or reset if there is a power
loss or electrical noise nor does it need to go through “learn speed” after power up or after
adjustments have been made.
Motor Control:
The
NB-4000
uses a state of the art
Regenerative (4-Quadrant) 90 VDC Motor Control
.
This provides the best assurance that the door’s high inertia characteristics will not
“overhaul” (or “freewheel”) the motor; thus, resulting in controlled door motion. The
NB-
4000
now features a
multi-speed board
that attaches to the top of the
motor control
. The
logic panel is greatly simplified with the elimination of the external speed pots and the
associated wiring. The new multi-speed board features control of (4) independent speeds.
The
NB-4000
now has the flexibility of controlling separate creep close speeds
(Preset 1)
and creep open speeds
(Preset 2)
as well as close speeds
(Preset 3)
and open speeds
(Preset 4)
. The motor control also features additional trimpots, which greatly improve the
performance of the drive and motion profile of such heavy doors. The
DB
(Dead Band)
trimpot sets the amount of main speed trimpot rotation to initial output voltage and controls
the amount of delay before regeneration starts. If not properly set, the motor may oscillate
or continue to hum. The
RESP
(Response) trimpot adjusts the dynamic response of the
system; therefore, increasing this setting will increase response time( if set too high ,
unstable operation may result). The
IR Comp
trimpot determines the amount in which the
motor speed is held constant as the motor load changes. For example, if set too low, the
motor may not obtain the desired speed fast enough or not at all. If set too high, the motor
may oscillate. The
RCL
(Reverse Current Limit)
trimpot and
FCL (
Forward Current Limit)
trimpot adjusts the armature current limit or motor torque in their respective directions.
When properly set, the operator will have sufficient torque to operate in both directions,
