Delta RMC101 - Manual (Page 800)

RMC100 and RMCWin User Manual
C-30
The Acceleration Feed Forward provides a second order approximation ( prediction ) of how
much drive is required to move.
If the position unit is 0.001 inches, this equals millivolts of drive per 100 inches per second per
second.
Why Bother?
The acceleration feed forward helps the axis track better while accelerating or decelerating. The
acceleration feed forwards should not be adjusted until the velocity feed forwards are adjusted
correctly.
C.2.14 Retract Acceleration Feed Forward
Default: 0
Range: 0 to 65535
Same as Extend Acceleration Feed Forward, except it is used when retracting.
C.2.15 Dead Band Eliminator
Default: 0
Range: 0 to 2000
Some valves and drives do not react to small changes in output around the null drive value; this
effect is termed "dead band". The Dead Band Eliminator helps alleviate this problem by applying
extra drive.
The RMC100 has two different Deadband eliminator algorithms:
• Proportional (recommended)
The number of millivolts specified in the Dead Band Eliminator value is added to or subtracted
from the drive output (depending on the direction of travel) when the Actual Position is outside of
the In Position window. This causes the drive to be outside of the deadband. When the Actual
Position is within the In Position window, the drive is applied proportional to the distance from
the actual position. The Integral gain is always held at its current value. This algorithm is the
recommended algorithm.
• Immediate (RMC100 default)
The number of millivolts specified in the Dead Band Eliminator value is always added to or
subtracted from the drive output (depending on the direction of travel) so the drive output is
outside the dead band.
Note: In RMC100 CPU firmware prior to 20030916, the Dead Band Eliminator always used the
immediate algorithm.
If a value outside the valid range is entered, the parameter error bit will be set, and the value will
be set to zero.