Wesley BC-620-4CA - Manual (Page 86)

82 Curtis 1234/36/38 Manual,
OS
11
d. Kp typically does not need to be changed as the default value will work
well in most applications. This parameter controls how tightly the ac-
tual motor speed will track the requested speed trajectory (speed trajec-
tory is set by the accel, decel, and brake rates).
If you want to adjust the Kp (for looser or tighter following of the speed
trajectory), follow these guidelines.
• Set the following parameters. Before setting them, make a note
of their present (default) settings so you can return them to
these original values at the end of this procedure.
* If your vehicle has an EM Brake, set the Brake Type (page
46) to 1. This setting will release the EM Brake as soon as
interlock is asserted.
* In the Speed Mode » Response menu, set all the accel and
decel rates to their fastest values (0.1 seconds); this allows
better observation of the system response.
* In the Speed Mode » Speed Controller menu, set the Max
Speed to low value (≈1000 rpm), as high speed operation
is not needed to observe system response.
* Set Soft Stop Speed parameter to 0 rpm to disable the soft
stop speed function (see Restraint menu, page 38).
• Cycle KSI to clear any faults.
• Using very quick, pulsing throttle movements, increase the
throttle and then release it to 0%. The intent is to give the
speed controller torque impulses.
• Increase Kp and repeat the throttle tests. Increase Kp until you
start to notice marginal stability (normally motor bouncing, or
continuous oscillation in the gears, is heard). Note: It is possible
that very heavy vehicles will not experience marginal stability
even at the highest setting of Kp.
• Once the Kp setting for marginal stability is found, reduce
the Kp value in the 1311 by about one third (i.e., final Kp =
marginal stability Kp * 2/3).
• If you will be using Speed Mode Express, enter this Kp value
for the Kp parameter in the Speed Mode Express menu.
• Set the Brake Type, Accel/Decel Rates, Max Speed, and Soft
Stop Speed back to their original values.
e. In the Speed Mode » Response menu, adjust the five Accel and Decel Rate
parameters as necessary while moving the throttle to different positions
(i.e., neutral to full throttle, half throttle to full throttle, full throttle to half
throttle, full throttle to neutral, neutral to low throttle, etc.). For AC pump
applications, these parameters are typically set very fast for quick response
to hydraulic inputs.
6 — TUNING GUIDE