Victor 884s not working

[aks.cristion.filwr]

We are using vex victor 884s to try and control 2 dc motors. Our code works...the arduino is outputing the correct voltage corresponding to the pwm I input in LabVIEW. 50% duty cycle for 128 pwm, etc...

The problem is that the victor isn't outputing the correct voltage. We had to set our oscillascope to 200mV per division to see a 50% duty cycle. We got the victors to work fine with a straight arduino code. I don't understand why it isn't working now. Has anyone else had a problem with this? I know this isn't LabVIEW code, but does anyone have any advice?

[QuantumReversing]

So when you measured the voltage drop with the code using the Arudino Environment, you took the measurements from the (+,-) posts on your motor controllers?

Some equations you probably have already messed with:

DutyCycle = (tau)/T

(tau) = RC

T = 1/f

And assuming you did the exact same procedure for the LabView code... It is hard to say becaue part of me wants to say it is the internal resistance of your DMM and O-scope that are coming into play but I dont think that is why. I know in arduino if you supply a potential (voltage drop) of less that 7V (example 5V from USB cable) the readings of voltages you measure will be off due to the internal resistance (step down resistor) of the arduino. But that still doesnt explain why it worked using the code from arduino and didnt when you used LabView.

Make sure your O-scope is set to DC coupling, count your squares that relate to the voltage division and see if they add up to the voltage you expect at a certain duty cycle, also make sure your ground line for "A" or "B" which ever output port you're using on the O-scope is right at the x-axis. Also are you even getting a square wave?

[aks.cristion.filwr]

Yeah, we took the measurements at the +,- outputs of the victors that goes to the motors.

I've looked over those equations, but I don't know how to apply them to our code.

I checked and our o-scope is set to dc coupling. We are getting square waves for the output of our arduino from 0 V to 0.6 V (enough for logic, yes?).

Our theory is this...victors want to see a pulse between 1 and 2 ms, but the pulses the arduino is sending out are between 0 and 1 ms. So we just need to at 1 ms to the pwm signal. Do you know how to do that, by any chance?

[CarlosOtiniano]

Greetings, The Victor module in a power control ara brush motors, ete module must receive at least three types of signals from a receiver RC helicopter or airplane 1ms - 1.5 ms - 2 ms, although the arduino can sign over signals with pulse width modulation does not guarantee that this will be interpreted by the victor, something similar happens if they can control servo motors servo motor with arduino can also communicate with the module nimgun victor no problem, good luck

[Kristoff2]

Can you post your Arduino code (that worked) and the LabVIEW Code using LIFA that doesn't work.  If so we might be able to track down the differences.

-Sam K

LIFA Developer