IAI PSEL, Operation Manual

Page: 849 / 1062

[12] Actuator
Control
Command
355
(Note) If the specified travel distance is equal to or less than the travel distance per
encoder pulse [mm/pulse], the axis may not move.
[Calculation formula of travel distance per encoder pulse]
Rotary encoder
Travel distance per encoder pulse [mm/pulse]
= (Screw lead [0.001mm] × Gear ratio numerator)
/ (Encoder resolution [pulses/rev] × Gear ratio denominator
/ (2 ^ Encoder division ratio)
Linear encoder
Travel distance per encoder pulse [mm/pulse]
= Encoder resolution [0.001
P
m/pulse] × 1000
/ (2 ^ Encoder division ratio)
(Reference) Use the values of the following parameters for the above calculation
formulas:
Encoder resolution
: Axis-specific parameter No. 42
Encoder division ratio : Axis-specific parameter No. 43
Screw lead
: Axis-specific parameter No. 47
Gear ratio numerator : Axis-specific parameter No. 50
Gear ratio denominator : Axis-specific parameter No. 51
(SCARA robots)
(Note 1)
If an incremental movement command (MVPI, MVLI, TMPI or TMLI) is used
repeatedly, coordinate conversion rounding errors, etc., will accumulate. To
eliminate these errors, etc., execute an absolute movement command (MOVP,
MOVL, etc.) once.
[Example 1] MVLI 6 Move from the current position by the travel
according to position No. 6.
If the current positions of the axes are specified by
position No. 5 (200, 150, 50, 45) and travels are
specified by position No. 6 (15, 30, 20, 30), the axes
move to the positions (215, 180, 70, 75).
(Note) In the case of a SCARA axis, the axis operates according to all-axis parameter
No. 11, “Default CP acceleration for SCARA axis” or all-axis parameter No. 12,
“Default CP deceleration for SCARA axis” if the acceleration/deceleration is not
specified in the position data or using an ACC (DCL) command.
In the case of a linear axis, the axis operates according to all-axis parameter No.
200, “Default acceleration for linear axis” or all-axis parameter No. 201, “Default
deceleration for linear axis” if the acceleration/deceleration is not specified in the
position data or using an ACC (DCL) command.
Caution
A margin of error could accumulate between each pitch if the incremental (relative position
indication) movement commands are repeated continuously.
To avoid accumulation of errors, utilize the movement command to indicate the absolute
position (MOVL Command).