Next you need to increase the value of KP gradually (maximum allowed is 1023.875). 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 by about 20%. 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.
Note: 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.
Example 1 - 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 (or X) axis gain
KPX=10 Method for setting only X (or 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
Example 2 - Profiled Move
Rotate the A axis a distance of 10,000 counts at a slew speed of 20,000 counts/sec and an acceleration and
deceleration rates of 100,000 counts/s2. In this example, the motor turns and stops:
PR1000 Distance
Chapter 2 Getting Started • 25 DMC-40x0 User Manual
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