Electrical systems – 5000

Table 9: Functional description

Event:

13. Initial forks lowering

Prior event(s) 2

Action(s) Press the lower forks button

Influencing elements

Resulting conditions

Forks lower button [A2:S22]

Lift height < 100mm, S32 [A1:INP. CABIN/FORKS LOWER THAN 100mm] activated (option)

[A1:OUT.LOWER VALVE] goes low

[A36:OUT.INITIAL FORKS SOFT CLOSING VALVE] goes low

Forks lowering hydraulic valve [Y10] activates.

Cabin hydraulic soft closing valve [Y69] activates. When S32 [A1: INP. CABIN/FORKS LOWER THAN 100mm] is not activated, pallet to ground protection or footprotection is active. (option)

10.4.1 Description of steering system

The servo steering system on this truck comprises a synchronous DC motor (M6) with permanently magnetized rotor which is also brushless. This type of motor is ideal for truck steering applications due to light weight and high torque even from stand still. The motor directly drives the drive wheel gear unit, via an integrated 2 stage planetary gear. The steer motor is controlled by a fully electronic 4-quadrant regulator (A5) which is mounted directly in the servo motor casing. Hall sensors (H) in the servo motor provide timing information for commutation control.

The sensors also provide the steer servo with position information. A double potentiometer (R2) mounted in the tiller unit provides steer angle information from the operator. Every time the traction battery is connected and the truck switched on the steer system performs a reference search for "straight ahead" position. An inductive proximity switch (S65) mounted in the final drive gear mounting plate registers a change in state (either ON to OFF or OFF to ON depending on drive wheel's initial position) and feeds this signal back to the steer servo. From this point on, the steer servo "knows" the position of the drive wheel. Only efter the traction battery is next disconnected, is a new reference search carried out. The steer servo communicates fully via the CAN bus. All steer servo errors codes are transmitted to the truck's control system and displayed on the tiller unit's display.

10.4.2 Spider expansion unit (SEU)

The Spider expansion unit, referred to as the SEU, allows the main control card to handle a greater number of inputs and outputs. The SEU allows up to 8 extra digital inputs and 4 digital outputs which can be addressed and controlled via the CAN bus. The SEU contains firmware but this is only for internal configuration. No truck control logic is present in the SEU. This means a faulty SEU can be exchanged without affecting the truck’s functions in any way.

There are 3 cases covering the usage of SEU: a) The SEU can be fitted if the truck is modified according to a customer special request. In this case, correct operation of the modification is acheived by adjustment of service parameters 16 to 19. b) The SEU is fitted as standard in certain truck models, to allow control of standard features. Such trucks do not require that service parameters 16 to 19 be activated. (Parameters 16 to 19 shall be set to “0”.) c) Trucks fitted with an SEU as standard can also have additional modifications using “configurable options”. These additional modifications are controlled by the setting of service parameters 16 to 19.

Refer to section Parameter #16 to #19 configurable options on page 51 for more detailed information.

Fig. 1 shows how the SEU is used to allow a greater number of functions to be controlled via the CAN bus. The SEU has one 42-pin multipin connector which handles all inputs, outputs, CAN and supply signals.

Electrical systems – 5000

10.4.3 Speed limitation

The truck's maximum travel speed is limited depending on a combination of factors, i.e. direction of travel, load, load lift height, steering angle, the operator's driving position and the platform height. Operator parameter settings also affect maximum speed. See Description of operator parameters on page 37 for more information. The table below summarises the speed limitations and assumes that all relevant operator parameters are set to 100%. Note that the speeds given are nominal.

Table 10: Summary of speed limitations

1. In this position, is displayed.

2. In this position, is displayed.

3. If the operator is not standing on the platform in this position, is displayed. Neither lifting nor truck travel can be operated in this case.