Kyle Grathwol
Member
Does anyone know how to convert a PWM output to an analog output?
Thanks in advance for your time.
Thanks in advance for your time.
I need an analog output for a project that I am starting. The components that I am leaning toward using only offer a PWM output. This component is a chip level plc device. This device will need to operate proportional directional control valves. The valve driver I use needs an analog input to send out a mA current to control the valves.What's the PWM coming from?
What's the analog coming from?
Details, as much as you can provide.
The key is to get the right information. What information is that?What's the PWM coming from?
What's the analog coming from?
Details, as much as you can provide.
None of this is obvious to me as this is the first time I have been faced with this situation.The obvious answer is to put a RC filter on the output. The next obvious thing is that you need to determine what the value of the resistor and capacitor. The current must be limited to less than what the analog card can supply.
The required analog signal is very low mA. It will just be a signal to a valve driver that out puts say a 0 to 1500mA current in proportion to the 0-5v analog signal it is receiving. The PLC device that I want to use can only supply a PWM output signal so I need a method to convert a PWM to analog output. Everything must be small form factor. The PLC device is chip level. Everything must fit in a very small enclosure.The key is to get the right information. What information is that?
I have until January. Come the first week of January I need to have finalized the component list.Kyle Grathwol, do we have all weekend to get the answer or do you need it ASAP.
Kyle Grathwol said:The required analog signal is very low mA. It will just be a signal to a valve driver that out puts say a 0 to 1500mA current in proportion to the 0-5v analog signal it is receiving. .
Kyle I suspect the 1500ma aspect rules out many options. You might still need a RC network on the input but perhaps something like this will work for you.
http://www.pwmcontrols.com/
Peter Nachtwey said:The only reason I will go on is if others want to get a small lesson on how low pass filters are implemented in hardware. There must be an educational value
I assure you that I am not trying to go the cheap way out.Too often I see people buy cheap and then waste a lot of time implementing their cheap solution