Chapter 4
What You Need to Know about Moves
©
National Instruments Corporation
4-13
NI 73
xx
Arc Move Limitations
The following are limitations to the velocity and acceleration of arc moves.
Arc moves must use the following equations or an
NIMC_invalidVelocityError
is generated:
and
where
V
= Velocity in counts/s
P
= PID sample rate in seconds
I
= Arc Interval (10 ms or 20 ms) in seconds
R
= Radius in counts
Arc moves must use the following equations or an
NIMC_invalidAccelerationError
is generated:
and
where
P
= PID sample rate in seconds
I
= Arc Interval (10 ms or 20 ms) in seconds
R
= Radius in counts
A
= Acceleration/deceleration in counts/s
2
V P
×
4
R
≥
×
1,677,216
V P
2
×
83,443
×
(
)
R I
×
-------------------------------------------
16
≥
≥
A P
×
4
R
≥
×
65,536
A P
3
×
83,443
×
R I
2
×
--------------------------------------
1
≥
≥
