TAPPET ASSEM. 9L9630 - Caterpillar

Illustration 1 g01266002
Components of the Truck Payload Measurement System.
(1) TPMS Indicator
(2) TPMS switch
(3) Transmitter
(4) Radio remote payload display
(5) Load cells
(6) Payload lamps
(7) Payload pivot pins
(8) Service tool
Illustration 2 g01266004
Location of the Truck Payload Measurement System components (typical example)
(1) TPMS indicator
(2) Switch
(3) Transmitter
(5) Load cells
(6) Payload lamps
(7) Payload pivot pins The Truck Payload Measurement System (TPMS) determines the weight of the payload. The TPMS measures the deflection of load cells (5) and payload pivot pins (7) as the truck is being loaded.TPMS indicator (1) sends an electrical current to load cells (5) and payload pivot pins (7). The electrical current passes through the strain gauges that are fitted to load cells (5) and payload pivot pins (7). Load cells (5) and payload pivot pins (7) deflect when a load is applied, this causes the strain gauges in load cells (5) and payload pivot pins (7) to stretch. This restricts the flow of electrical current through the strain gauge. The changed electrical current is returned to TPMS indicator (1). TPMS indicator (1) interprets the difference between the current sent to the strain gauges and current received from the strain gauges. The difference is then converted to a digital reading and the weight is displayed on TPMS indicator (1).TPMS indicator (1) sends a signal to payload lamps (6). Payload lamps (6) will change from green to red when the target payload is reached.When radio remote payload display (4) is used, TPMS indicator (1) sends a radio signal to radio remote payload display (4) via transmitter (3). Radio remote payload display (4) will display the same information as TPMS indicator (1).The TPMS must be calibrated prior to placing the truck into service. The TPMS measures deflection of load cells (5) and payload pivot pins (7). This represents the weight of the empty body and is recorded in the memory of the TPMS during calibration. The TPMS uses the weight of the empty truck body to calculate the weight of the payload. The TPMS subtracts the weight of the empty body from the weight of the material that has been loaded into the body.Reference: For the correct procedure to calibrate the TPMS, refer to System Operation, Troubleshooting, Testing and Adjusting, "Calibration".