7i92 pwm to 0-10v analog

Hi guys.
i am a little bit confused.
I get from amazon a pwm to 0-10v converter.
I try it out first on a arduino which has 5v outputs on the GPIOs. works fine.

then i switched to my 7i92 and 7i92t!
i reach only 9v -9.04v if i screw in the calibration cap.
In the hal i set different pwm base freq. from 1khz up to 30khz. nothing helps.

then i come to the point that the optocoupler on the converter isolate the circuit. this means for me it doesnt matter which voltage is coming from the mesa right?

what are the cause?
i dont search for circuit diagramms..

the idea what i have was to take a lm358 and make it on a breadboard..

but i ask here before waste my time.

thanks

 

i dont do it over a wizard.. only by hand... in the hal and ini.

The most likely cause is that the PWM --> voltage converter is
not using a Rail to Rail output (RRO) OP-AMP. 

The same thing will happen if you use your LM358, it will only
swing up to ~8.5V or 9V with a 10V supply. If you want 10V from
your  converter, you would need to use say a 12V supply. 

i supply 12v... thats the thing.
i dont know the circuit but i think.. the 3.3v are not the reference voltage.
after the optocoupler i meassure a 5v signal of the pwm. is it possible that i need to invert it? or is it the wrong way?
direct on the output of the lm358 i meassure 9.5v at 100% pwm.
then it goes over resistor and cap to the output. down to 9.04v

but.. with the arduino same khz i get 10v....

Maybe the OPTO input circuit requires 5V?

I guess you could test this by simple supplying +3.3VDC
to the input and seeing if you get 10V out

If you need 5V drive, you could put a stiff pullup
on the PWM pin to +5V (say 330 Ohm)

I guess it could also be a scaling issue
 a PWM value >= PWM scale will result in a fullscale
(stuck high) output

makerhero.com/img/files/download/3PSC3-m...bOy1GiYJwCPiI6EEGEI2

i talk about this thing... and i test now 500hz up to 3khz in 5ü0hz steps.. nothing changed.. i have 3 of them.

i wonder because the arduino brings the converter to 10v.

That data suggests a 4.5V minimum input PWM voltage.

Also, if it has an optocoupler input, you can get a 5V signal
out of a 7I92/7I92T by wiring the PWM input to +5V and the PWM
input negative to the PWM output of the 7I92/7I92T.
In this case, you would need to invert the PWM output in
your hal file.