SMAC
LAC-25 Technical Reference Manual
21
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, i n
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
