SSC-32 + LYNXTERM + Commands doesn't turn servo completely

[silverbyte]

I have a very annoying problem, Im hoping some one could help me out.

when I execute : #0 P2000
It turns a little. But not to the full position. If I keep executing : #0 P2000
it will keep on turning, but i need to keep executing : #0 P2000
it will ONLY stop turning once I reached the P2000 position. then executing the same command #0 P2000] will do nothing.

So I thought maybe I neeed to specify the time so it can fully execute the turn. (which doesn’t sound right… but doesn’t hurt to debug)

Then I executed : #0 P750 T1000
Same thing. It rotates the opposite direction, with a small pulse.
I need to KEEP executing #0 P750 T1000] or #0 P750] to reach its 750 position.

Do i need to keep executing the commands until I reach that position ? this sounds cumbersome (system wise since it will be flooding the RX/TX signals with constant data)

What am i doing wrong?, can anyone help me debug this? I used 3 different servos, 2 are the same, the other is a futaba. All same results.

Im only attaching 1 servo at a Time for now, and Im only supplying power to VL

note: connection @ 115baud works, but in lynxterm it spits out a wierd letter ‘y’ (with 2 dots ontop)… if i reduce the baud to 38.4 I don’t get that anymore… but same results… it does not complete its turn

Any help would be appreciated. Thank you
(oh and p.s… i thought this was a firmeware proble, so i updated to the latest 2.03)

[wowy7]

This may or may not be a dumb question, but are you forgetting the (Carriage return) at the end of your lines?

[silverbyte]

no question is a dumb one…
but if i didn’t send the it wouldn’t move at all… so no thats not it

BUT I FIGURED OUT MY PROBLEM!

I was SHARING VL (voltage for logic) with VS (voltage for servos). Upon reading somewhere I found out that the SSC-32 can RESET ITSELF if drops in voltage…

This explained a little why it started to move…then stopped. Repeatedly sending the command would start moving… voltage dropped and my servo would stop moving again… This is what was happening.

SOOOOO I increased the voltage to 7.2 volts

I send the command : #0P2000

THIS TIME It turned MORE… infact at one point it turned all the way… what was happening ??? voltage dropout… completely random…

so I took my smaller servo, and I timed my turn using this command

#0 P2000 T2000
TO MY SURPRISE IT WORKED!!!

with the smaller servo, I can control easily with 7.2v @ 300mAh, although I need to supply extra voltage to my servos, or else it will reset itself, and not work properly.

TADA!!! it took me 2 days to figure that out

[wowy7]

Glad you figured it out.

[robotdude]

@silverbyte

TADA!!! it took me 2 days to figure that out

Sorry it took so long for you to figure it out. Your problem is happening because your power supply does not have enough current capacity for the servos. You need like 2 amps, not 300mA.

It’s covered in great detail in the ** Troubleshooting Information** section of the SSC-32 manual.
lynxmotion.com/images/html/b … tm#trouble

Specifically…

@The Guide

Troubleshooting Information

If you notice the servos turn off or stop holding position when moving several servos at one time, this indicates that the SSC-32 has reset. This can be verified by noticing if the green LED is on steady after the servos are instructed to move. The green LED is not a power indicator, but a status indicator. When the SSC-32 is turned on, the LED will be on steady. It will remain on until it has received a valid serial command, then it will go out and only blink when receiving serial data.

The SSC-32 has two power supply inputs. The logic supply (VL) powers the microcontroller and its support circuitry through a 5vdc regulator. The servo supply (VS) powers the servos directly. In single supply mode (default) the jumpers VS1=VL will provide power to the CL 5vdc regulator from the VS terminal. This works great for battery use, and with most wall pack use, as long as the voltage does not drop too much. However, if it does drop, the voltage to the microcontroller is interrupted and the SSC-32 resets. To fix this you remove the VS1=VL jumper and connect a 9vdc battery clip to the VL input. This isolates the servo and logic supplies so one cannot affect the other.

Using the single supply mode is generally safe for the following conditions:

VS of 7.2vdc 2800mAh NiCad or NiMH battery packs for up to 24 servos.
VS of 7.4vdc 2800mAh LiPo battery packs for up to 24 servos.
VS of 6.0vdc 1600mAh NiCad or NiMH battery packs for up to 18 servos.
VS of 6.0vdc 2.0amp wall pack for up to 8 servos.

Note, these are just general guidelines and some exceptions may exist. The only other thing that can cause this effect is a poor power delivery system. If the wires carrying the current are too small, or connections are made with stripped and twisted wire, or cheap plastic battery holders are used, the same problem may occur. 99% of problems with the SSC-32 are power supply related. If you are noticing erratic or unstable servo movements, look at the power delivery system.

[silverbyte]

I noticed that " Troubleshooting Information" After I figured it out

But thanx for the update. thats why w have forums, and I see you have a nice little community going on here.

Sometimes its good to debug stuff on your own, I find you learn more this way. I can’t wait to start controlling massive amounts of servos with my ARDUINO!!! woohoo!