SMAC
LAC-26 Technical Reference Manual
4/29/2013 14
Command:
aFVn -- Feed-forward, Velocity --
Argument:
0 <= n <= 32767
Default:
0
This command allows for the adjustment of the PID digital filter velocity feed-forward term for
servo axis 'a'.
During the course of a Position Mode (PM) or Velocity Mode (VM) move, at any point along the
way (with a consistent load), the ideal required value of the servo output is fairly consistent and
somewhat predictable.
During acceleration or deceleration:
OUTPUT = (VELOCITY * FV_CONSTANT) + (ACCELERATION * FA_CONSTANT)
During constant velocity:
OUTPUT = (VELOCITY * FV_CONSTANT)
If this value can be dynamically predicted and summed with the output of the PID digital filter, in effect, it
reduces the burden of the PID filter to make lead/lag corrections based of the following error, thereby
enhancing performance.
Related Commands: FA, OM, OO
Command:
aGRn -- Gear Ratio --
Argument:
-8388607 <= n <= 8388607
Default:
0
This command sets the electronic gearing ratio for axis 'n'. A negative argument will cause a
direction reversal in the electronic gearing. The argument to this command is the desired gearing ratio
scaled by 65536.
Examples:
GR65536
; Slave gear ratio is 1:1
GR131072
; Slave gear ratio is 2:1
GR32768
; Slave gear ratio is .5:1
GR6554
; Slave gear ratio is .1:1 (actual gear ratio is
; .100006103516:1).
GR-65536
; Slave ratio is 1:1 with direction reversal
Related Commands: EG
Command:
aILn
-- Set Integration Limit --
Argument:
0 <= n <= 16,383
Default:
0
This command clamps the level of influence that the PID digital filter integral term can use to
reduce the static position error of servo axis 'a'. When properly adjusted, this can enhance loop stability
and operation. The Integral Limit (IL) and Set Integral Gain (SI) must both be set to a non-zero value in
order for the integral term to have any effect.
Related Commands: SI