The earliest Otis GEN-II MCS220 elevator weighing system installed four weighing sensors and an LWB weighing board on the frame of the car floor. The weighing board was connected to the MCB-II board through CAN-BUS communication, and the four weighing sensors were used to obtain the weight analog voltage of passengers in the car. This allowed the GENG-II elevator to be given a reasonable pre torque when starting or stopping, providing good comfort when braking. When the comfort was abnormal, the service tool MCB-II board was tested, and the service tool error note M-2-2-1 was recorded. After pressing the shift+3 on the service tool, the following faults may occur

1. ALW: LWB Board

Possible reasons: internal errors or abnormalities in the weighing device board,

Solution: Replace the weighing device version LWB

2. ALW: Load Sensor

Possible causes of malfunction:

1) Detected at least one load cell malfunction or damage

Solution: Replace the weighing sensor

2) The GAIN data of the weighing device board is abnormal.

Solution: Perform GAIN correction adjustment

3) The output voltage of the sensor is abnormal, and the voltage is not between 2000 (2V-7V) millivolts and 7000 millivolts

Solution: Adjust the pressure of the weighing sensor to a suitable range of 2000 (2V-7V) millivolts to 7000 millivolts

3. ALW: CAN Bus

1) Fault cause, possible cause: communication loss between MCB-II board and LWB2 board

Solution: Check the connection of the CAN communication line

2) Abnormal power supply on LWB2 board

Solution: Check MCB P5:6- MCB P5:5 DC (+15V) (HL2)

3) MCB-II board damaged

Solution: Replace the MCB-II board.