Galil DMC-2X00 - Manual (Page 41)

For more damping, you can increase KD (maximum is 4095). Increase gradually and stop after the
motor vibrates. A vibration is noticed by audible sound or by interrogation. If you send the command
TE A <return> Tell error
a few times, and get varying responses, especially with reversing polarity, it indicates system vibration.
When this happens, simply reduce KD.
Next you need to increase the value of KP gradually (maximum allowed is 1023). You can monitor the
improvement in the response with the Tell Error instruction
KP 10 <return> Proportion gain
TE A <return> Tell error
As the proportional gain is increased, the error decreases.
Again, the system may vibrate if the gain is too high. In this case, reduce KP. Typically, KP should
not be greater than KD/4 (only when the amplifier is configured in the current mode).
Finally, to select KI, start with zero value and increase it gradually. The integrator eliminates the
position error, resulting in improved accuracy. Therefore, the response to the instruction
TE A <return>
becomes zero. As KI is increased, its effect is amplified and it may lead to vibrations. If this occurs,
simply reduce KI. Repeat tuning for the B, C and D axes.
For a more detailed description of the operation of the PID filter and/or servo system theory, see
Chapter 10 - Theory of Operation.
Design Examples
Here are a few examples for tuning and using your controller. These examples have remarks next to
each command - these remarks must not be included in the actual program.
System Set-up
This example assigns the system filter parameters, error limits and enables the automatic error shut-off.
Instruction Interpretation
KP10,10,10,10 Set gains for a,b,c,d (or A,B,C,D axes)
KP*=10 Alternate method for setting gain on all axes
KPA=10 Method for setting only A axis gain
KP, 20 Set B axis gain only
Instruction Interpretation
OE 1,1,1,1,1,1,1,1 Enable automatic Off on Error function for all axes
ER*=1000 Set error limit for all axes to 1000 counts
KP10,10,10,10,10,10,10,10 Set gains for a,b,c,d,e,f,g,and h axes
KP*=10 Alternate method for setting gain on all axes
KPA=10 Alternate method for setting A axis gain
KP,,10 Set C axis gain only
KPD=10 Alternate method for setting D axis gain
KPH=10 Alternate method for setting H axis gain
DMC-2X00 Chapter 2 Getting Started y 31