User Guide
Lynxmotion SSC-32U Servo Controller Board
Electronics Guide
Example 2 will move servo 3 to position 1600. It will take 1 second to complete the move
regardless of how far the servo has to travel to reach the destination.
Multipleservocommand(a.k.a.“CommandGroup”)
The SSC-32U allows for multiple commands to be received in the same string. For servo
position, this may look like:
# <ch> P <pw> S <spd>
... # <ch> P <pw> S <spd>
T <time> <cr>
Commands of different types cannot be mixed in the same command group. Note that the
<time> function should be placed at the end of the line and is associated with the entire move,
whereas the <speed> command can be associated with each servo.
Example 1: #5 P1600 #10 P750 T2500 <cr>
The example above will move servo 5 to position 1600, servo 10 to position 750, and it will take
2500 milliseconds (2.5 seconds) to complete the move, even if one servo has farther to travel
than another. The servos will both start and stop moving at the same time. This is a very
powerful command. For example, by commanding all the legs in a walking robot with “Group
Move” it is easy to synchronize complex gaits. The same synchronized motion can benefit the
control of a robotic arm as well.
You can combine the speed and time commands if desired. The speed for each servo will be
calculated according to the following rules:
1. All channels will start and end the move simultaneously.
2. If a speed is specified for a servo, it will not move any faster than the speed specified
(but it might move slower if the time command requires).
3. If a time is specified for the move, then the move will take at least the amount of time
specified (but might take longer if the speed command requires).
Example 2: #5 P1600 #17 P750 S500 #2 P2250 T2000 <cr>
The example provides 1600uS on ch5, 750uS on ch17, and 2250uS on ch2. The entire move
will take at least 2 seconds, but ch17 will not move faster than 500uS per second. The actual
time for the move will depend on the initial pulse width for ch17. Suppose ch17 starts at position
2000. Then it has to move 1250uS. Since it is limited to 500uS per second, it will require at least
2.5 seconds, so the entire move will take 2.5 seconds. On the other hand, if ch17 starts at
position 1000, it only needs to move 250uS, which it can do in 0.5 seconds, so the entire move
will take 2 seconds.
Important! The first positioning command should be a normal "# <ch> P <pw>" command.
Because the controller doesn't know where the servo is positioned on power-up, it will ignore
speed and time commands until the first normal command has been received.
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