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Moog Animatics SmartMotor™ Developer's Guide, Rev. L
Page 171 of 909
Modulo Position
Modulo Position mode allows the user to define maximum position counter rollover. Normally,
the shaft position counter can run anywhere from zero to ±2
31
. This means the motor counter
will continuously increase in the positive direction, and when it hits its maximum, it will
instantly go negative and begin counting down to zero. With Modulo Position mode, the user
can set up an alternative counter that will increase up to a given value and then roll directly
over to zero and start counting up again. The count will never go negative; it will always be
0<=modulo value<=(Modulo Limit-1).
This mode is especially useful in rotary pan or azimuth controls for targeting systems, radar,
and camera bases. Combined with the Combitronic™ interface, multi-camera surveillance
systems can pass subject tracking from one pan & tilt to the next.
Modulo Position Example
For the previous figure:
l
PML= 360 (Position Modulo Limit) maintains counts between 0 and 359 degrees.
l
PMT= 270 (Position Modulo Target) takes the shortest path to the specified target
position (270 degrees).
Modulo Position Commands
The following commands are used to set and read the modulo position. For more details, see
Part 2: SmartMotor Command Reference on page 238.
PML=formula Set the modulo limit. The modulo counter reports between 0 and this
value minus one. By default, this is 1000. The minimum value is
1000. This command resets the modulo count to 0.
=PML
Reads the modulo limit currently set.
PMT=formula Set a target for a position move in terms of a modulo position. The
motor takes the shortest path to reach this value. This means that
the motor may move in either a clockwise or counter-clockwise
direction, depending on which one produces the shortest motion in
modulo terms.
=PMT
Reads what was set for the modulo target.
Part 1: Programming: Modulo Position