Model 5200 High-Level Orderpicker

Lift/Lower Lift

The lift/lower potentiometer (VR2) commands the carriage to lift. When the lift knob is rotated, the lift/lower proportional solenoid valve (normally open) stays open while the lift contactor closes. After th e contactor closes and the lift pump motor turns ON, the proportional solenoid valve ramps closes, forcing hydraulic fluid into the cylinders and increases lift speed. The proportional solenoid valve provides a smooth transition between zero speed lift and full speed lift and back to zero speed lift. When the lift knob is released, the proportional solenoid opens and the lift contactor opens turning OFF the lift pump motor. During lift, the load-holding solenoid valve remains closed (de-energized).

The microprocessor on the Steer/Tractor Manager verifies the lift contactor remains closed when commanded closed, and open when commanded open. If either condition is not met, the Steer/Tractor Manager generates a fault code.

Section 8.Theory of Operation Lift/Lower

1.As the control handle lift knob is rotated, a voltage is applied to JPC13-6 on the Carriage Manager.

2.The Carriage Manager sends a lift command message to the Steer/Tractor Manager over the transmit/receive lines.

3.The Steer/Tractor Manager provides the negative potential for the lift pump contactor coil (JPT12-18) and the pump contactor coil is energized. The lift pump contactor LED (IL6-5) on the Steer/Tractor Manager indicates the pump contactor coil driver is energized.

4.When the lift pump contactor coil is energized, the lift pump contactor tips close supplying B+ to the lift pump motor.

5.The Steer/Tractor Manager provides the negative potential for the lift/lower proportional solenoid valve coil at JPT12-8, indicated by the solenoid control LED (IL6-7) on the Steer/Tractor Manager. The lift/lower proportional valve begins to ramp closed (this valve is normally open).

6.The lift pump/motor assembly is now running and supplying hydraulic pressure and flow to the lift cylinders.

Publication Number: 1043922B, Revised: 2 Sept 2015

Section 8.Theory of Operation

Lift/Lower

Lower

The lift/lower potentiometer (VR2) commands the carriage to lower. When the lower potentiometer is rotated, the lift/lower proportional solenoid valve closes and the load-holding solenoid valve opens. The proportional valve opens and allows hydraulic fluid to return from the lift cylinders to the reservoir.

When lower is no longer requested, the proportional valve opens and the load-holding valve closes.

1.As the control handle lower knob is rotated, a voltage is applied to JPC13-6 on the Carriage Manager.

2.The Carriage Manager sends a lower command message to the Steer/Tractor Manager over the transmit/receive lines.

Model 5200 High-Level Orderpicker

3.The Steer/Tractor Manager provides the negative potential for the lift/lower proportional valve coil at JPT12-8, indicated by the load-holding solenoid LED (IL6-7) on the Steer/Tractor Manager. The lift/lower proportional valve ramps closed (this valve is normally open).

4.The Steer/Tractor Manager provides the negative potential for the load-holding valve coil at JPT12-9, indicated by the load-holding solenoid LED (IL6-9). The coil energizes and the load-holding valve opens.

5.The Steer/Tractor Manager varies the negative potential for the lift/lower proportional valve coil at JPT12-8, indicated by the load-holding solenoid LED. The lift/lower proportional valve gradually opens allowing hydraulic fluid to return to the reservoir.