Reading value of a PWM valve with a PWMIN

Andy Pauly 2 years ago in Master modules / MC4x updated by Gustav Widén (System support) 2 years ago 1


A stand alone system have 4x PWM proportional valves in 24VAD. I use a MC43. 

I like to ready this PWM value so that my system can give the right amount of oil from the variable pump. 

I like to use the PWMIN.  IN_33 and IN36 are for 5Volt sensors. Can I still use this INputs?? or do I need to use IN-37 and IN_38 because they are the only one rated to 24V. Can I somehow use a resistor so that I can use the 5Volt PWMIN.?? Sorry:  I am not sure even reading you documentation. 

We have a 6.8 Kohm pulld down resistor in the modules, so putting a 20-25 Kohm resistor in series on the input would bring down the voltage from 24 V to 5-6 V.

But you can have 32 V continuous on the PWM inputs.

What you need to look out for is the trigg levels, those are below 1 V for low and above 4 V for high.

So the PWM signals need to go below 1 voltage for the signal to be read correctly, The high you should not have any issue with.

Could you check the signal with a ocilloscope to see how low and high the signal actually goes?