Rpm Sensor; Maximum Run Timer - Chamberlain T Owner's Manual

RPM Sensor/Auxiliary Reversal System (Programming is Recommended)
Feature: By programming the RPM sensor to a specific application, the logic
board learns the speed the door travels with reference to the spinning
motor. This sensor activates the start winding and recognizes clutch
slippage.
Benefit: By removing the centrifugal start switch from 1/3 and 1/2 horsepower
single-phase motors the leading cause of motor failure is eliminated.
The auxiliary reversing benefits of the RPM sensor are designed to
prevent excessive door and operator damage upon hitting a solid
obstruction. LiftMaster recommends the use of safety devices for
primary safety protection.
To Program:
1. The open and close limits must be set before setting the RPM sensor.
2. Start with the door closed and turn all dip-switches to the off position.
3. Press open then press and hold the "learn" button on the Logic board until the
door reaches the full open position. You should see the Learn LED turn off
after pressing the learn button; it will turn back on about 5 seconds later. If the
LED did not cycle, start over and wait about 1/4 to 1/2 second between
pressing "open" and "learn."
4. Return the dip switches to your regular wiring type (C2, B2, etc.) and close the
door.
Note: LiftMaster 2.0 Logic operators are designed to work in most cases without
adjusting the RPM sensor. It is still recommended to set this feature on every
installation. This feature will need to be reset if the motor or logic board is ever
replaced.
Maximum Run Timer (Setting is Recommended)
Feature: The door will run in one direction for a set amount of time. Default time
is 90 seconds. Installer can adjust the 90 second timer to the open
cycle plus 10 seconds.
Benefit: Should the door hit an obstruction that is not detected by a sensor, it
will stop after the programmed amount of time and not continue to drive
into the obstruction. This may help prevent prolonged human
entrapment as well as help prevent damage to the door and operator .
To Program:
1. Start with the door closed and the limits set.
2. Set the dip switches to "set Max Run Timer".
3. Press Open and wait for the door to reach the full open limit.
4. Return the dip switches to the desired wiring type (C2, B2, etc.) and Close the
door. The Maximum Run Timer is now set and will allow the door to move in one
direction no more than 10 seconds longer than it normally takes to travel from
close to open.
Example: If it takes the door 13 seconds to open normally, the operator will stop
running after 23 seconds. If the Max Run Timer is not programmed, it will run for
90 seconds total in either direction.
Note: For very large, slow moving doors, where the normal travel time is close to
90 seconds setting the MRT is essential to move the door the full travel distance.
STANDARD PROGRAMMING FEATURES
17
ON
ON
SET
MAX RUN
TIMER
1 2 3
OFF
4