Generating a PWM Pulse with xpctarget through PATI Board

I'm using xpctarget to generate a pulse via a PATI board. I am generating this PWM signal with the "PATI MPL PWM Generate" block in order to control a servo. When the servo is connected to the PATI board and I run the model on xpctarget, the servo shows no movement. The servo will however move when connected to RC input. I then measured the pulse that the RC emits with an oscilloscope. and set the high and low counts to match this pulse. When the PATI board is connected directly to the oscilloscope, it shows the same pulse that the RC had shown. The only difference is the RC gives off a signal Voltage of 3V while the PATI board gives a signal voltage of 5V, this should not be an issue though because the servo should be able to work within that range. My question is now two-fold. Firstly, why does the seemingly identical signal only work in RC and not the PATI board? The other question is how do I generate a pulse that has a "High" pulse of 3V through the PATI board. If I'm able to do this, I'd be able to rule out the voltage difference as the reason for error.

Answer 1

[Gordon Weast]

I'm not sure what's happening with this. If you have the PATI output connected to your device and measure it with the oscilloscope, does the output still get to 5 volts? There could be a loading issue here. Your device might need more current than the board can supply. If that's the case, you would need to do some signal conditioning on the output, perhaps as simple as a higher current device that can drive the voltage you need being driven by the PATI.

The output voltage of the PATI can't be reduced. It's just an on or off signal and the board uses 0 and 5 volts.