CONTREX M-Traverse - Manual (Page 4)

CP-9 Accel/Decel Length
The Accel/Decel Length (CP-9) parameter allows the Follower mechanism to ramp to either the constant pitch plateau
or end dwell, either gradually or rapidly. This parameter is the number of encoder lines for the desired Accel/Decel
Length.
CP-10 Dwell
The Dwell (CP-10) parameter allows the Follower mechanism to pause at the end of the Follower profile before ramping
back in the opposite direction. This parameter is a portion of the encoder lines in one revolution of the reel (Lead).
TUNING
If your system is unstable, or the position error is unacceptable, tuning may stabilize your system or reduce the
position error differences between the setpoint and feedback. You can achieve a stable system using conservative
values in the Tuning Control parameters, however the position error may be unacceptable. On the other hand,
aggressive values in the Tuning Control parameters may cause the system to become unstable. The goal is to reduce
the position error to the level that you want, yet maintain the system’s stability.
To achieve an acceptable level of position error, increase the Gain (CP-65) parameter until the system becomes
unstable then reduce the CP-65 incrementally until the system stabilizes. In systems that require greater accuracy, it
may be necessary to adjust the Integral (CP-66) parameter to reduce any remaining position error.
CP-65 Gain
To adjust the Gain term, first enter a value of zero into CP-66 (Integral). With the M-Shuttle running at the maximum
process speed, increase the value in CP-65 until the system starts to become unstable (instability can be observed by
erratic motion or audible disturbances). Once the point of instability is found, reduce the CP-65 value slightly until the
system stabilizes.
CP-66 Integral
If your system error is unacceptable after adjusting only the Gain term, it may be necessary to add some Integral to
reduce the final position error. While running at maximum process speed, add slight increases to the Integral term (CP-
66) until the error is reduced to an acceptable level (note: leave the Gain term in when adjusting Integral).
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