Delta RMC101 - Manual (Page 46)

Appendix B: Tuning RMC100 Startup Guide
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Only" will make the RMC ignore the errors so you can tune the axis. This may
not be possible on some systems because of safety concerns. Remember to set
these bits to either "Soft Stop" or "Hard Stop" when you have gained sufficient
control of the axis.
• When changing the parameters, remember that they are not updated in the
RMC until the Set Parameters (P) command is issued. They are not
stored into the RMC FLASH memory until the Update FLASH command
is issued.
Tuning a Position Axis
The following procedure may be used to tune many hydraulic position axes and
motors in velocity mode.
1. Set all Gains and Feed Forwards to zero
This is done by editing the values in the main RMCWin window. Then click
the to initialize the RMC100.
2. Set the Null Drive
The drive it takes to hold the axis in position is referred to as the Null drive. If
the axis tends to drift significantly when you give it an Open Loop drive of 0,
you should set the null drive. This drive is then always added to the total drive
output and helps the RMC100 accurately follow the motion profile. To set the
null drive, issue a P command to hold the axis in position in closed loop, then
issue the N command.
3. Check Dead Band
If your system has a large dead band, you will need to set the Dead Band
Eliminator value. To find your dead band, give increasing amounts of drive to
the system with the Open Loop command. The value of drive at which the
system starts to move is your dead band. If this value is approximately 400 or
greater, the Dead Band Eliminator should probably be used. If it is less, it is
left to the discretion of the designer.
4. Adjust the Proportional Gain
The Proportional Gain must be adjusted to gain some control over the system
for continuing the tuning procedure. Adjust the Proportional Gain by slowly
increasing it and making moves. When the system gets close to final position
reasonably quickly, continue to the next step. If the system begins to oscillate,
decrease the gain.
5. Adjust the Feed Forwards
In many hydraulic systems the feed forward parameters (Extend Feed Forward
and Retract Feed Forward) are the most important parameters for position
tracking during a move.
Make a long move without any oscillation or overdrive. Then issue the Set
Feed Forward command. This command will automatically adjust the Feed
Forward parameter for the direction of that move.
6. Adjust the Acceleration Feed Forwards
The Acceleration Feed Forward terms help eliminate following errors while
accelerating. It is particularly useful for systems moving large masses with
relatively small cylinders. Such systems often have a delay before the start of