Retract feed forward (pressure), Integrator preload (pressure), C.5.11 retract feed forward (pressure) – Delta RMC101 User Manual
Page 841: C.5.12 integrator preload (pressure)
Appendix C: Parameter Field Reference
C-71
changing. This value is expressed in terms of millivolts per 1,000 Pressure Units per second.
Extend Feed Forward drive is added to the output only when the axis is extending. The drive
output provided by the Extend Feed Forward is determined as follows:
To set the Feed Forward parameters, try ramping the pressure with very small gains. If the axis
lags after this parameter has been set, the feed forward is too small or the system response is too
slow. If the axis leads, the feed forward is too large or the system response is too slow.
Note:
Because pressure does not necessarily react linearly to the drive output (that is, the same
amount of drive does not increase the pressure by the same amount at all positions), it is
important to tune the Feed Forwards at the particular pressure ramp that will be used. If you will
be ramping the pressure multiple times, you may want to use the 0xD8 and 0xD9 commands to
set these parameters between pressure ramps.
Think about this:
On hydraulic systems, the extend and retract feed forward terms will be different by the ratio of
the extend and retract surface areas of the position.
C.5.11 Retract Feed Forward (Pressure)
Default: 100
Range: -32768 to 32767
Note:
Use positive Feed Forward and Gain values if the pressure increases in the extend
direction, and negative values if the pressure increases in the retract direction.
Same as Extend Feed Forward, except it is used when retracting.
Note:
Retracting is the direction that returns decreasing Transducer Counts.
C.5.12 Integrator Preload (Pressure)
Default: 0
Range: -32768 to 32767 (millivolts of drive)
The value of this parameter represents millivolts of drive that will be placed in the integral drive
term at the time when the pressure axis begins controlling pressure. Some applications require
this additional drive (either positive or negative) immediately on the transition.
Note:
If this term is non-zero, then it is important that the Integral Gain also be non-zero.
Otherwise, the initial integral drive will never return to zero and the pressure may never reach
the requested pressure.