Curtis 1244-64 series - Page 84

A-2
Curtis 1244 Manual, Rev. E
APPENDIX A: GLOSSARY
Braking rate
e braking rate is the time required for the controller to increase from 0 to 100%
braking current when braking is requested. e braking rate is a MultiMode™
parameter and is programmable from 0.1 to 5.0 seconds—see Section3, page 26.
CAN Bus
CAN (Controller Area Network) Bus provides a two-wire communications
system for electric vehicles. It is widely used in automotive applications and
is also well suited to electrically controlled material handling systems. Use of
the CAN Bus system considerably reduces the complexity of the vehicle’s wire
harness. Additionally, the CAN Bus communications protocol provides error
and fault detection to ensure proper signal and command transmission and
reception. e CAN Bus system carries a high level of immunity to electro-
magnetic interference, as well. For information regarding the CAN-Nodes
protocol that Curtis uses in its controllers, refer to the Curtis CAN Protocol
Document—available from local Curtis offices.
Control mode
e control mode parameter determines whether throttle position controls
applied current (Type 0) or applied voltage (Type 1). Selection is made with
the programmer—see Section 3, page 28.
Creep speed
Creep speed is activated when a direction is first selected. e output maintains
creep speed until the throttle is rotated out of the throttle deadband (typically
10% of throttle). Creep speed is a MultiMode™ parameter and is programmable
from 0 to 25% of the PWM duty cycle—see Section 3, page 27.
Current limiting
Curtis controllers limit the motor current to a preset maximum. is feature
protects the controller from damage that might result if the current were limited
only by motor demand. PWM output to the armature and field power sections
is reduced until the motor current falls below the set limit level.
In addition to protecting the controller, the current limit feature also
provides some protection to the rest of the system. By eliminating high current
surges during vehicle acceleration, stress on the motor and batteries is reduced
and their efficiency enhanced. Similarly, there is less wear and tear on the vehicle
drivetrain, as well as on the ground on which the vehicle rides.
e drive and braking current limits are programmable independently in
each of the four modes—see Section 3, page 36.