4 — PROGRAMMABLE PARAMETERS
Curtis 1232E/34E/36E/38E & 1232SE/34SE/36SE/38SE Manual, os 31 – May 2017 Return to TOC
pg. 38
1- SPEED MODE — POSITION HOLD MENU
PARAMETER ALLOWABLE RANGE DESCRIPTION
Position Hold Enable PCF
|Position_Hold_Enable
|Position_Hold_Enable_Bit0 [Bit 0]
0x3893 0x00
On / Off
On / Off
Allows the Position Hold mode to be entered at zero throttle when the vehicle
comes to a stop.
NOTE: EM Brake Type = 2 also enables the Position Hold function
Position Hold Timeout Time
Position_Hold_Timeout_Time
0x388C 0x00
0.0 – 20.0 s
0 – 625
This parameter plus the Position Hold Settling Time parameter sets the maximum
time the vehicle will stay in Position Hold before releasing the hold and going into
Restraint mode. Setting the parameter to zero disables this timeout function, which
means the Position Hold will be held. Activating the interlock resets the timer.
Kp
Kp_Position_Hold
0x388A 0x00
2 – 100%
82 – 2048
Determines the stiffness with which position is regulated when in Position Hold
mode. High Kp will produce less rollback on a ramp, but more bouncing; see Kd
below. Too much Kp will cause instability.
Kd
Kd_Position_Hold
0x388D 0x00
0 – 100%
0 – 8192
Determines the damping in Position Hold mode. Some damping must be present
in the control system to keep the vehicle from oscillating slowly (“bouncing”).
High Kd will improve the dynamic response of the Position Hold controller, but too
much Kd will cause fast instability.
Zero Speed Threshold
Zero_Speed_Threshold
0x306F 0x00
5 – 100 rpm
5 – 100
Determines the speed below which the EM brake will be commanded to set.
Setting this speed too high may cause a jerky stop when the EM brake sets and
stops the motor.
This parameter appears twice in the menu structure. Changing the value of this
parameter affects this (same) parameter in the EM Brake Control menu, page 49.
This parameter is re-named for os31. It is the same as the previous Set
Speed Threshold parameter.
Zero Speed Threshold Time
Zero_Speed_Threshold_Time
0x30DA 0x00
0 – 480 ms
0 – 60
Determines how long motor speed must be below Zero_Speed_Threshold to
declare zero speed.
This parameter appears twice in the menu structure. Changing the value of this
parameter affects this (same) parameter in the EM Brake Control menu, page 49.
This is a new parameter for os31
Position Hold Settling Time
Position_Hold_Settling_Time
0x3024 0x00
0 – 5000 ms
0 – 156
Determines how long the position hold function is allowed to operate before the EM
brake is set. This time should be set long enough for the position hold to settle.
This parameter appears twice in the menu structure. Changing the value of this
parameter affects this (same) parameter in the EM Brake Control menu, page 50.
This parameter is re-named in os31. It is the same as the previous Set Speed
Settling Time parameter.
Entry Rate
Entry_Rate_Position_Hold
0x383B 0x00
5 – 100%
50 – 1000
When the vehicle transitions from forward speed to reverse speed or from
reverse speed to forward speed (for example when coming to a stop going up
a steep ramp) Position Hold is automatically entered immediately at zero speed
regardless of this parameter.
This parameter applies when the vehicle needs to be brought to a stop without
the assistance of gravity (for example when moving forward down a ramp).
This rate determines how quickly zero speed is attained after the ramped
speed request reaches zero. Setting this parameter too high will make the stop
seem very abrupt and may even cause the vehicle to roll back slightly. When
the parameter is set lower the vehicle take longer to come to a stop and enter
Position Hold mode.
Exit Rollback Reduction
Exit_Rollback_Reduction
0x3844 0x00
0 – 100%
0 – 2048
This function is applicable when the Torque Preload Enable function has been
Disabled (Off) or the Torque Preload Cancel Delay timer has expired (see EM
Brake menu). Exit Rollback Reduction is only intended for use with EM Brake
Type = 2, for EM Brake Type = 1 (or 0) set Exit Rollback Reduction = 0.
Exit Rollback Reduction introduces an additional control function for the speed
controller to reduce rollback on a ramp after a throttle command is applied from
a stop. For example, suppose the vehicle is on a ramp facing upwards and, after
a forward throttle request, the vehicle rolls back slightly before climbing the ramp
(again, assuming the torque preload function is inactive). As the vehicle rolls back,
this additional term will be added to the torque request until forward speed is sensed,
to attempt to minimize rollback. The effect increases with percentage, and is disabled
when = 0%. Setting the value too high may introduce temporary oscillations.
If the Torque Preload Cancel Delay parameter expires before the throttle is re-
engaged, the torque preload [Position Hold] memory will be cleared. In such a
case, setting Exit Rollback Reduction to > 0% will reduce unintended roll. (see
page 51).
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