Controlled Roll-Off; Hill Hold; Inching - Sevcon Gen4 Applications Reference Manual

Controlled roll-off

WARNING: Controlled Roll-Off is not recommended for on-highway vehicles as it can
cause the traction motor/wheel to remain locked or brake severely if the wheel is
momentarily locked due to loss of traction on a slippery surface and/or mechanical
braking.
Controlled roll-off limits a vehicle to a slow, safe speed if it starts to move without any operator
input. Primarily, it is to prevent uncontrolled movement if a vehicle's brakes fail on an incline.
Controlled roll-off operates whether the operator is present or not.
Configure the following at object 2930

Enable/disable controlled roll-off

Set a roll-off maximum speed

Set a roll-off maximum torque
Alternatively, Gen4 can apply an electromagnetic brake if one is mapped and roll-off is detected.
Refer to 'Electro-mechanical brake' on page 6-34 for more information.

Hill hold

WARNING: Hill Hold is not recommended for on-highway vehicles as it can cause the
traction motor/wheel to remain locked or brake severely if the wheel is momentarily
locked due to loss of traction on a slippery surface and/or mechanical braking.
A vehicle on a hill can be held at a standstill for a configurable time when the operator selects
neutral. At the end of this time or if the seat switch indicates the operator is not present, hill hold
terminates and the vehicle can start to move if parked on an incline. If enabled, the system will
enter controlled roll-off after hill hold.
You can set the hill hold delay at object 2901
In speed mode, drive torque is disabled whilst neutral braking to stop. However, drive torque
must be re-enabled when entering Hill Hold to allow torque to be applied to hold on the incline.
Set the speed to re-enable drive torque at 2908

Inching

WARNING: Ensure inch switches are only mapped to digital inputs when required.
Activation of these inputs can cause a drive condition to occur.
Inching allows an operator to manoeuvre a vehicle, at low speeds, towards a load. Inching can
be initiated with one switch. A time-out is used to prevent the vehicle from continuing to drive
indefinitely if the switch gets stuck or goes short circuit.
To configure inching:

Ensure forward and reverse inching switches have been mapped to two digital inputs.

Specify an inching speed (0% to 25% of the full speed of the vehicle) at 2905
This is either a speed target in speed mode, or maximum speed in torque mode.

Specify an inching throttle (0 to 100%) at 2905
torque mode. This is not used in speed mode.

Specify a time-out (0.1 s to 5.0 s) at 2905
6-30
:
h
. Set the hill hold delay to 0 to disable this feature.
h
.
h
sub-index 3. This gives a torque target in
h
sub-index 2.
h
sub-index 1.
h