Page 30 SC2000 Manual – 177/52301 Rev G 22
nd
October
2004
10.2.5 Power Steer speed - On compensated pump systems this setting can be used to control the
power steer speed from the main pump motor. This speed is selected from the power steer
trigger input as previously described and can be compensated for as described in the section
below. The power steer also has independent ramp up and ramp down delays. See the
section 9.1.11 on Power Steer for more information.
10.2.6 Pump Inhibit Input
- This input can be used in conjunction with external equipment such as
a separate BDI unit for example, to disable Pump operation when the battery is low. All Pump
speeds are inhibited at the end of the operating cycle, except the Power Steer speed.
10.2.7 Pump Speed Compensation
- Some trucks utilise the main hydraulic pump motor to provide
power steering assistance, instead of a separate power steer motor. This feature provides
speed compensation so that the pump motor always provides steering assistance, whilst
allowing the motor to slow down when assistance isn’t required to minimise noise and
improve efficiency. Pump speeds 1 - 4 and the Power Steer speed can be compensated if
required.
The compensation is a straight line characteristic set up using 2 personalities. The set up
procedure may require some repetition to give optimum performance of low load (low noise)
and full compensated load. The low load speed is normally set up to run the pump motor at
its lowest permissible lubrication speed to keep audible noise to an absolute minimum.
The calibrator’s base speed sets up the low load speed and the compensation factor sets the
amount of boost when the controller detects a current increase due to the pump motor load
increasing. The controller monitors the motor current and changes the motor voltage to
ensure that the motor remains on this compensated speed line.
Set up Procedure - Set both the base speed and the compensation factor to 0. Activate the
pump switch associated with the speed to be compensated. Ensure that the motor has its
minimum load. Increase the Base speed until the correct operating speed at minimum load is
achieved. Increase the load associated with this pump speed to its maximum. Increase the
compensated speed until varying the load has little or no effect on the speed.
Example - Power steer compensation where the main pump motor provides the hydraulic
steering assistance. Set the Power Steer personality base speed and compensation factor to
0. Activate the Power Steer Trigger input and increase the Power Steer base speed until the
pump motor is running at its desired low speed. Operate the steering. Very little assistance
will be given if the pump is going slow. Increase the Power Steer compensation setting until
the required amount of assistance is given when the steering is operated. The set-up is an
iterative process so it may be necessary to change the base speed again and repeat the
procedure to obtain optimum results.
10.2.8 Pump Bypass/F.Weak
- This contactor output will energise 1.0 second after the pump has
reached full speed (100% on), and can be used to switch a contactor across the main Pump
Mosfet device to act as a Bypass contactor, or it can switch a contactor with a series
resistance to act as a Field weakening contactor.
10.2.9 Pump Contactor on Standalone Traction Units - On standalone Traction controllers a pump
contactor can be fitted that is operational from any of the pump 2 -5 switches. Operating
these switches on a standalone traction unit will also increment the pump hours count.
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