F3: System Mode
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Load Weigher Thresholds
This menu does not appear if the ANALOG LOAD WEIGHER option in the EXTRA FEATURES
MENU is set to NONE. The load weigher (isolated platform, rope tension or crosshead deflec-
tion) provides a signal that corresponds to the perceived load in the car. This signal is brought
to the control system where it is conditioned, sampled and digitized, and the value is used to
calculate the actual load inside the elevator. This load value is then used for logical dispatching
operations. The load thresholds are user-programmable and determine when each of these log-
ical operations should be performed.
• LIGHT LOAD WEIGHER (LLW): This value is used to define the load at which a lim-
ited number of car calls is to be registered (anti-nuisance). If the programmed number of
car calls is exceeded, all car calls will be canceled.
Example: LLW=20%. If the measured load in the car is less than 20%, the computer
will only allow a certain number of car calls to be registered, defined by the parameter
LIGHT LOAD WEIGHING? / LIGHT LOAD CAR CALL LIMIT in the
EXTRA FEATURES MENU OPTIONS. If the limit is set to a value of three, the
computer will only allow three calls to be registered if the load is less than 20%. If a
fourth call is registered, all car calls will be canceled.
• DISPATCH LOAD WEIGHER (DLW): This value is used to define the load at which
the lobby landing door timer is reduced. This threshold should be set to a value (defined in
many specifications as 60%) at which it is appropriate to initiate the process of moving the
car out of the lobby.
• HEAVY LOAD WEIGHER (HLW): This value is used to define the load value at which
hall calls should be bypassed.
• OVERLOAD WEIGHER (OLW): This value is used to define the load at which it is
considered unsafe to move the elevator. When this threshold is exceeded, the car will
remain at the floor with doors open. Typically an application that requires OLW will use
some type of visual and/or audible indicator to alert elevator passengers that the car is
overloaded.
Adjusting the Load Thresholds
The typical values for the load thresholds are shown below. However, these thresholds are user-
adjustable and may be changed at any time.
To adjust these thresholds:
1. Enter the SYSTEM mode of operation by placing the F3 switch in the up position.
2. Press the N push button until LOAD WEIGHER THRESHOLDS appears on the LCD
display.
3. Press the S push button to display the load threshold you wish to set.
4. The value shown is the current threshold value expressed as a percentage of the full load
value (see the table above). Press the '+' or '-' push button to adjust the value. If the
value is set to 0%, the load weigher function is disabled.
5.
Press the S push button to select another load threshold to adjust or press the N push
button to exit this menu.
6. Place the F3 switch in the down position to exit SYSTEM mode when finished.
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