Rockwell Automation 8520-ARM2 9/Series CNC AMP Reference Manual Documentation Set User Manual

Page 727

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Tuning a Digital or Tachless Analog System

Appendix A

A-5

Download AMP with the following consideration:

Configure all velocity loop parameters as listed in Table A.A. You
should be able to set most of the parameters to their final values (such as

number of counts per rev and velocity feedback port).

Configure your linear Acc/Dec Curve for an acceleration/deceleration
ramp at a slope close to (but slightly less than) your expected maximum

servo acceleration slope (see appendix B for assistance). Your entire

Acc/Dec curve must be entirely below the curve of the selected position

loop gain throughout the operating speed range.

Unfit the analog/out DAC port on each servo card in your system (9/230
controls only support one analog out connector). Typically these are

used as spindle ports. This is necessary to simplify the use of the DAC

monitor feature discussed later. If you can not easily access AMP to

make this change you can still use the DAC monitor however the DAC

monitor parameters apply to the servo cards with a fitted analog/out

DAC port first (see page A-6).

Configure the following spindle gear range parameters:

Voltage at Max for Gear 1 -- set to 10 volts

Max Spindle Speed Gear 1 -- Set to 3000 RPM

The settings for gear range one scale the output of the DAC monitor.

You may need to adjust the RPM value later depending on the feedback

resolution for the axis you are tuning.

Servos must be homed before they can be programmed and tuned. This
can prove inconvenient since homing an untuned servo can be dangerous

and damaging to hardware.

This homing requirement can be avoided through PAL. The flag $HMNO

is available which causes the control to believe the selected axis has

already been homed. Write PAL to set the bit of $HMNO that corresponds

to the axes being tuned. Refer to your PAL Reference Manual for details

on using the switchless homing feature.

ATTENTION: Using the switchless homing feature can cause

invalid/inaccurate software overtravels and programmable

zones. Confirm that the hardware overtravel switches are

functioning properly. Make sure that the axis’ position when

the tuning part program is executed does not violate any of

these areas.

A.1

AMP for Tuning

A.2

PAL Considerations

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