View Full Version : Propeller Servo Controller USB not working the next morning

04-09-2012, 03:01 PM
my Propeller Servo Controller USB stopt working, it was running perfect the day before ,
and the next morning i boot up my pc and the servos are not responding any more.
the lights still blinking but the servos only holds the center points, and servo 14 gets no power
i conected the my second Propeller Servo Controller USB and its working perfect.
can someone pleas tell me what's gone wrong .


Mike Green
04-09-2012, 03:16 PM
Can't tell you what's wrong without much more information, measurements, etc. Something unusual happened to the first Servo Controller. Given that the 2nd Servo Controller works fine, that pretty much eliminates problems with cables and power supplies, although there could be intermittent problems. I suggest you call Parallax Tech Support. They may have you send in the Servo Controller and replace it.

04-09-2012, 03:32 PM
What are you using on the PC to communicate with it? Are you using your own application or the PSCI software? If you are using the PSCI software can you see the com port and select it and then have it get the version of the controller? That will verify that it can actually still talk to it. Each of the controllers will should be coming up on it's own com port on the PC.

As Mike mentions, if you can provide more details that would certainly help.

04-09-2012, 05:09 PM
thanks i will contact Parallax Tech Support,
but i'm from the netherlands and dont know the costs of sending it to Parallax

i use roboreal and this controller(its new,2 days old) to tilt and pan my cameras.
yes i seem to can communicate with it using the usb connection,
even the Propeller tool has access the eeprom/ram.
i hoped it lost data or something like that ,but i'm afraid it died when i turnd off my pc
maybe some kind of feedback ,if thats even posible
whit the PSCI software i have connection but the servos do not react to it anymore.


04-09-2012, 07:15 PM
What are you using as the power supply for the servos?

How many servos are connected?

What is the brand and Model number of each servo? Some people (myself included) have run into issues with some servo's and needed to install a 10K resistor inline or the servo control signal.

I checked out the RoboRealm site and it looks like they talk to the controller at the default 2400 baud rate so it should be the same as the PSCI software.

04-09-2012, 08:25 PM
4x 1.2volt batteries for servo supply, at thad moment a robbe s3003 and a robbe fs 100.
indeed i also had dying servos on a ne555 servo controller i build a while ago.
when a 8 or 10k signal resistor installed it was ok.
did your servos die or your controller?

do you know if its posible the Propeller Servo Controller can be damaged when the pc is turnd of and on again,when
for example the Propeller Servo Controller still gets his power for the servos?

at his moment i do not even dare to turn of the pc, i think ill let it run to night

04-09-2012, 08:39 PM
I haven't had any servos die (unless stripped gears count but that was un-related) and my servo controller is ok. The only issue I had is that some servos weren't working and I had to add a 10K resistor inline with the servo signal wire in order to get it resolved. From posts in other threads I believe that has to do with the 3.3V to 5V translator chips.

I can't see why just turning off your computer would have damaged your board. Maybe the defaults for the servos in the upper EEPROM are somehow corrupted and it thinks the servos are disabled to it isn't trying to control them. Clearing the EEPROM data may correct that. Alternately you could try to download the firmware from the product page and try to reload that. I'm going that route on mine since I am only using 7 servos and 8 of the lines are going to be for LED lighting instead.


Mike Green
04-09-2012, 08:40 PM
The Propeller is protected from the USB bus (and the PC) by the FTDI USB to serial adapter chip and the Propeller is protected from the possibility of a bad servo letting 5V get through to the control lines by the 5V to 3.3V interface chip. Even if something was wrong with the USB port on the PC, there's a 3.3V regulator (very robust) protecting the Propeller from the 5V USB power supply. A lightning strike on the power line could damage the PC's USB port and get through the FTDI chip to damage the Propeller, but you'd probably see signs of damage in the PC (and it probably wouldn't work).

04-10-2012, 12:17 PM
thanks guys i really needed to hear dis, in adder words it is a very good protected unit
and it's unlikely it got damaged, instead there is a big chance its memory is corrupted.
this morning i connected it again and almost all servo working again.(i dont know way)
only servo channals 14 and 3 are not responding.
i think this is the firmware source code name ,PSC Propeller Firmware.
using compile current i can send this to the unit then reset it,but makes no divrance
tried to make the clear eeprom source file but i'm not capable to(yet)
i copyd this text from manual pdf into a new source file,
' {$STAMP BS2}
' {$PBASIC 2.5}
Sdat PIN 15 ' Serial Data I/O Pin
Baud CON 396 ' Constant For 2400 Baud
buff VAR Byte(3) ' Temporary Variable (Array)
DEBUG "Clearing Upper EEPROM...", CR
SEROUT Sdat, Baud+$8000, ["!SCLEAR", CR]
SERIN Sdat, Baud, 600, Clear_EEPROM, [STR buff\3]
DEBUG "Reply: ", buff(0), buff(1), buff(2), CR
it tels me, pub is missing