OM6008 08/06 Payload Meter III - Section 60 Page 60-7 Payload Operator Switch The payload operator switch is used to set, view, and clear the total load counter and total ton counter. It is also used to enter the operator ID number (0-9999). This switch can also be used to view the suspension pressures and inclinometer. The payload meter oper- ator switch is located on the dashboard. It is a two- way momentary switch. The top position is the SELECT position. The SELECT position is used to step through the different displays. The lower posi- tion is the SET position. The SET position is used to set the operator ID or clear the load and total ton counters.
Normally the inputs from the switch to the payload meter are open circuit. The switch momen- tarily connects the circuit to ground. Payload Meter The payload meter is housed in a black aluminum housing. There is a small window on the face of the unit. Status and active alarm codes can be viewed through the window. During normal operation, a two- digit display flashes 0 back and forth. Active fault codes will be displayed for two seconds. These codes are typically viewed using the laptop computer connected to the serial communications port. There is one 40-pin connector on the payload meter. A jack-screw is used to hold the payload meter and wire harness connector housings together.
This screw requires a 4mm or 5/32 hex wrench. The cor- rect tightening torque for this screw is 2.8 N·m ( 25 lb- in.) . Four bolts hold the payload meter housing to its mounting bracket in the cab. Speed Input PLM III uses a speed signal to calculate speed, dis- tance, and other performance data. This input is criti- cal to the proper operation of the system. PLM III receives this signal from the speedometer/operator display on the dashboard. The same signal displayed to the operator is used by the system. Distance cal- culations are made based on the rolling radius of the tires for a particular truck.
The circuit board inside the payload meter housing is made from multi-layer, dual-sided surface-mount electronics. There are no field serviceable compo- nents inside. The electronics are designed to with- stand the harsh operating environment of the mining industry. Opening the payload meter housing will result in voiding the warranty. Communications Ports Body-Up Switch The body-up input signal is received from a magnetic switch located on the inside of the truck frame, for- ward the pivot pin of the truck body. This is the same switch typically used for input to the drive system. When the body is down, the switch closes and com- pletes the circuit to 71-control power.
24 VDC indi- cates the body is down. Open circuit indicates that the body is up. The payload meter has two RS232 serial communi- cations ports and two CAN ports. Connections for the two serial ports are available inside the payload meter junction box. The two CAN ports are available for future electronics systems. Serial port #1 is used to communicate with the dash- board display. It is also used to connect to the laptop computer. The display gauge will remain blank when the PC is using the serial port. This port initially oper- ates with serial settings at 9600,8,N,1. These set- tings change automatically to increase the communications rate when the PC is using the port.
This serial port uses a three-wire hardware connec- tion. Brake Lock Switch The brake lock is used to lock the rear brakes on the truck. It is necessary for the accurate calculation of swingloads during the loading process. Without the brake lock applied, the payload meter will not calcu- late swingloads during the loading process. Without the brake lock, the payload meter will assume that the truck was loaded using a continuous loader and flag the haul cycle record. All other functions will be normal regardless of brake lock usage. The brake lock input comes from the switch located on the dash panel. The brake lock switch connects the circuit to ground.
Open circuit indicates brake lock off. Ground indicates brake lock on. Serial port #2 is used to communicate to other on- board electronics like Modular Mining's Dispatch® system or the scoreboard from Komatsu. This port uses a three-wire hardware connection. Connections to this serial port need to be approved by Komatsu. Several protocol options are available and detailed technical information is available, depending on licensing.