Victor 884 Schematic Diagram

[Hugh Meyer]

Thank you for your ideas.

I am sorry this is in the wrong place. I intended it to go in the electrical section, but I got sidetracked looking at CAN, then forgot to go up one level before posting.

We are making a tester that our mechanical guys can use during the proto type design phase. They often want to run a motor to test some mechanism and have not had a good way to do that. Typically they would just connect it to the battery, but that gives them a false sense of power that is not really available when being controlled by the robot, because the battery is not very current limited. Or we would connect it to a control system, which is not very convenient.

The circuit is this device:
http://gadgetgangster.com/find-a-pro...projectnum=206

On a scope the signal looks just like the output from an IFI RC controller except for the voltage. With an 8 volt power supply the open circuit voltage is 8 volts, but connected to a victor it drops to 1 volt.

The Jaguar schematic shows an input to an optical isolator, which would be easy to interface to like Alan said using a series resistor. I would like to be able to use either a Jaguar or a Victor,

I would still like to find a schematic diagram for a Victor 884.

Thanks.

-Hugh

[AustinSchuh]

Originally Posted by Hugh Meyer

On a scope the signal looks just like the output from an IFI RC controller except for the voltage. With an 8 volt power supply the open circuit voltage is 8 volts, but connected to a victor it drops to 1 volt.

My understanding is that the Victors take more current to control than typical PWM controllers can source, which would explain exactly what you are seeing. I remember IFI selling "converters" that probably just amplify the current that the speed controller can draw from the PWM line. You can easily create a buffer with an op-amp and a 5 volt supply voltage. I also bet there are other chips that some of the other guys can point you to that also will "amplify" the signal.

[Al Skierkiewicz]

Hugh,
Are you saying you connected it to a Victor and it didn't work? The assembly instructions show the circuit connected to a Futaba 4.8 volt battery pack. It should produce standard RC remote signals that the Victor can use. Remember that if you are looking at the low side of the opto coupler then the voltage you see with a scope is the 5 volt supply less the drop across the diode and the series resistor. Remember that the Victor PWM input has a signal pin (White), a power supply pin(Red) and common pin (black). You must supply all three between the circuit and the Victor. There is the possibility you have damaged the Victor using the higher voltage. Try hanging a resistor of say 10K across the signal output and common (-) and then check with a scope. It should swing between power supply and zero volts.

[jason701802]

The simplest way to take care of this would be to just use a ~5 volt source to power the servo tester. Unless you have 5 volt source, the easiest way of getting 5 volts would by using a lm7805, $1.59 at RadioShack. Connect the left most pin to the power supply, the middle to ground, and the right one to the voltage input on the servo tester.

Better yet, if you haven't already bought the servo tester, find one with a regulated 5 volt supply or just make one yourself, it can be a great learning experience. There are many circuit diagrams for servo testers online (and probably even a few on Chief Delphi) that are based on the 555 timer chip (the same as the servo tester you linked to).

[Joe Ross]

IFI has not released schematics for their products. They do answer questions on their support forum.