Delta Computer Systems TMC 188/40 Series Manual page 29

TMC 188/40 Motion Control Module
STATIC GAIN (Default: 50)
STATIC GAIN specifies the amount of drive added to the drive output for a given amount of position
error while the axis is at rest (the AT COMMAND POSITION bit set). STATIC GAIN is given in
number of counts of drive per 100 units of error. The STATIC GAIN should be set as high as possible
without causing the axis to oscillate. See MAX ERROR parameter on page 32.
CAUTION: Increase the STATIC GAIN gradually. Excessive gain can cause oscillations which could cause
damage and injury.
EXTEND GAIN (Default: 50)
EXTEND GAIN is similar to the STATIC GAIN, except it applies when the axis is extending. The gain
while moving can usually be a little higher than at rest. This will allow tighter control of the axis while
moving. (Extending is the direction that returns increasing TRANSDUCER COUNTS.)
RETRACT GAIN (Default: 50)
The RETRACT GAIN is similar to the EXTEND GAIN except it is used only when the axis is
retracting.
INTEGRAL GAIN (Default: 50)
The INTEGRAL GAIN is used to adjust the drive developed by the integrator while the axis is moving.
The INTEGRAL GAIN field should be adjusted after the feed forwards have been set to optimal
values. Using the integrator before the feed forwards have been set properly will cause the system to
overshoot the command position.
When a 'G' command is issued, the integrator adds the position error (ACTUAL POSITION - TARGET
POSITION) to an accumulator every 2 milliseconds. As long as the error is not approaching zero or
has not changed sign, it is added to the accumulator. When the axis starts ramping down, the
accumulator is decremented at a rate calculated to bring the value to zero when the axis stops. The
drive provided by the integrator is given by:
Integral Drive =
DIFFERENTIAL GAIN (Default: 0)
The DIFFERENTIAL GAIN field is used to control the differentiator. The differentiator can be used on
systems that have slow response.
Differentiator Drive = (TARGET SPEED - ACTUAL SPEED) x DIFFERENTIATOR GAIN
CAUTION: To avoid oscillation during initial tuning, start with low values such as 1.
EXTEND FEED FORWARD (Default: 100)
NOTE: Use the 'F' command to automatically set the feed forward value. See page 38.
Feed forward is an open loop drive that is proportional to the TARGET SPEED of the axis. This value
is expressed in terms of counts of drive per 10,000 position units per second.
EXTEND FEED FORWARD drive is added to the drive output only when the axis is extending. The
drive provided by the EXTEND FEED FORWARD is determined as follows:
Delta Computer Systems, Inc. 360/254-8688
INTEGRAL GAIN x Accumulated error
10,000
Motion Control Parameters
100
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