Hi,
Just got my SSC-32 board along with 2 servos for controlling a camera. Fired up the lynxterm software and everything was good. The baud rate was 9600bps. Then I added a jumper to go to 115200bps. At that point “parallel” commands stopped working, that is moving 2 motors at the same time. Tried going back to 9600bps to no avail. More precise description of the problem is that commands of the sort #0PxxxTxxx work splendidly and the motor completes it’s move in the desired time. The same command without the time variable also works but when I do #0Pxxxx#1Pxxxx tings start to go wrong. Each motor only moves about 1/8 of the movement specified. Tried upgrading the firmware, no luck. Looks like some sort of race condition in the motor command scheduler…
Can you please provide a more complete description of the list of the commands you sent? The problem you are describing is simple stuff. the SSC-32 can do this with half it’s I/O pins tied up. Most people forget that the T command can’t be used as the first command after powerup and it can be confusing. Are you sure…
I would be suspecting the supply voltage. Especially as some things work a little bit, and the other is I may suspect mechanical problems except that no “weird noise” was mentioned.
Ok I’ll try. Setup is as follows. Power jumpers are connected in this manner, VL=VS1=VS2. Power:A Brand New 9v alkaline batterie. Motors: Two HiTec HS-422. The motors are are screwed together to provide 2 degrees of freedom to the head of a future humanoid robot.
As said earlier a command to each motor separately like this
#0P900<cr>#1P1700<cr>
works as expected, the first motor finishes before the second one starts and then the second motor starts. What we were doing and can’t do anymore is to send a command like this
#0P900#1P1700<cr>
to get “parallel” movement. That is if you imagine a head on the motors giving it the ability to move the head more naturally.
No nasty sounds or anything, just does not work anymore.
You need separate battery supplies for the electronics and the servos. That 9V battery does not have enough current to supply everything at once. Servos want a 6.0V power supply. You can power the electronics (VL) with a 9V battery just fine, but the servos (VS1 and VS2) need a separate 6V battery supply. This is the preferred arrangement, regardless of how many servos you have. You can have VS1=VS2 with this arrangement.
The other way to do this is to power everything from a nice 6.0V battery pack like those Lynxmotion sells. Then you can safely have everything powered from the same source (VL=VS1=VS2).
Since you are working on a humanoid robot, I would not recommend the HS-422 servos. Depending on what kind of humanoid you are building, you will need different servos (higher torque ratings for larger robots).
