Moog Animatics SmartMotor™ Developer's Guide,Rev. L
Page 123 of 909
PRT=formula
Set Relative Target Position
The PRT command allows a relative-distance move to be specified when the motor is in
position mode. The value indicates the encoder counts to travel; it must be within the range of
-2147483648 to +2147483647. This relative distance is added to the current trajectory
position and not the actual position either during or after a move. If a previous move is still in
progress, then the current trajectory position is added to when G is commanded. If the total
distance traveled needs to directly correspond to the number of moves made, make sure a
move has finished before issuing another G command.
ADT=formula
Set Target Acceleration/Deceleration
Target Acceleration/Deceleration must be a positive integer within the range of 0 to
2147483647. The default is zero, so a nonzero number must be entered to initiate motion. A
typical value is 100. This command sets acceleration and deceleration of the motion profile to
the value specified. This value can be changed at any time. The value set does not take effect
until the next G command is executed. Native acceleration units are
(counts/sample/sample)*65536. The default sample rate for Class 5 is 8.0 kHz; the default
sample rate for Class 6 is 16.0 kHz.
AT=formula
Set Target Acceleration Only
DT=formula
Set Target Deceleration Only
The AT and DT commands allow setting different values for the acceleration and deceleration
of the motion profile, respectively. Standard practice should be to use the ADT command
instead unless separate values are needed. There is an override that automatically sets DT
equal to AT if the motor power is turned on and only AT is set. However, this should be
avoided by using the ADT command when DT is not used.
To convert acceleration in revolutions per second
2
to units of ADT, AT or DT, follow this
formula:
ADT = Acceleration * ((enc. counts per rev.)/(sample rate
2
)) * 65536
If the motor has a 4000 count encoder (sizes 17 and 23), multiply the desired acceleration, in
rev/sec
2
, by 4.096 to arrive at the appropriate setting for ADT. With an 8000 count encoder
(size 34), the multiplier is 8.192. These factors assume a PID rate of 8.0 kHz, which is the
default.
Note that ADT, AT and DT allow only even numbers. When odd numbers are used, they are
rounded up. The default values are zero.
VT=formula
Set Target Velocity
The VT command specifies a target velocity (speed and direction) for velocity moves, or a
slew speed for position moves. The value must be in the range -2147483647 to 2147483647.
Note that in position moves, this value is the unsigned speed of the move and does not imply
Part 1: Programming: PRT=formula
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