Discription of function

Discription of function

- Road travel Important! When road travel switch S52 is locked, the max. no-load speed (full throttle) set, the 2nd gear engaged and the ground speed control lever (R39) in neutral position, the engine speed (B10) is 1100 rpm.When moving the ground speed control lever, the engine speed is increased proportionally to 1500 rpm. This control behaviour may change, resulting in the engine speed increasing further in case of higher loads on the ground drive (highpressure sensor B97/B98).

Ground drive - forward The ground drive forward solenoid valve (Y141) swivels the ground drive variable displacement pump. The ground drive variable displacement motor solenoid valve (Y144) swivels the variable displacement motor.Actuation is by the ground drive module (A49) in a pulse width-modulated manner (PWM).The respective swivel angles depend on: –ground speed control lever position (R39) –load on the ground drive (high-pressure sensor B97/ B98) –hydraulic motor speed (B99) = max. ground speed –field work or road travel mode (road travel switch S52). - reverse The ground drive reverse solenoid valve (Y142) swivels the ground drive variable displacement pump. The variable displacement motor is not swivelled in this process, remaining at a large input volume.Actuation is by the ground drive module (A49) in a pulse width-modulated manner (PWM).The swivel angle depends on: –ground speed control lever position (R39) –load on the ground drive (high-pressure sensor B97/ B98)

Pressure limitation When the high pressure measured by the high-pressure sensors B97/B98 reaches the maximum allowed value, the pulse width-modulated actuation (PWM) of the ground drive solenoid valves (Y141 and Y142) is reduced to a minimum by the ground drive module (A49). Service brake When actuating the left-hand (Z84, Z79-2) and the right-hand (Z85, Z80-2) service brake, the vehicle is decelerated hydraulically by the ground drive.Deceleration in the 2nd gear is greater than in 1st gear.

Brake light activation by EFA ground drive (for Speedstar only)

At a ground speed of > 3 km/h, the brake light lights up even if the hydrostatic ground drive decelerates the vehicle. If a theoretical deceleration of the ground speed of > 10% is set at the ground speed control lever, the ground drive module A49 sends a corresponding message to the fieldwork computer (CAB) module A10 via the CAN bus. The fieldwork computer (CAB) module A10 activates the brake light via relay K36 until the target speed set at the ground speed control lever is reached (see diagram 35). EMERGENCY BRAKE When actuating the left-hand (Z79-1) and the right-hand (Z80-1) service brake with a minimum force of more than 600 Newton, the power supply of solenoid coil Y143 is interrupted. The control oil pressure in the ground drive collapses and the variable displacement pump/motor swing back to zero displacement regardless of the ground speed control lever position. Note: To reactivate the electro-hydraulic ground drive, move the ground speed control lever to neutral position.