Hi folks.
I have been working on my CHP project ...(http://www.navitron.org.uk/forum/index.php/topic,12943.0.html) and due to the limitations of the PLC that I am using (It was free) I need to build a frequency to voltage interface board.
I would like to convert frequency to voltage, I am currently working with 50 Hz but could change this by modifying the shaft encoder. Assuming the target stays at 50 Hz I will need a 0 -10v signal that represents 40 60 Hz ideally, although 0 60 Hz would probably work all be it with lower resolution.
I appreciate that a simple integrator looking at the square frequency will work but if I use a cap big enough to limit the ripple to an acceptable level then the system is far to slow.
I probably need some sort of sample and hold circuit looking at each individual pulse width but really dont know where to start.
Any input would be greatly appreciated.
( I have some analogue switch ICs, bought to multiplex the PLC inputs, if that helps at all. )
Thanks
Alistair
I have been working on my CHP project ...(http://www.navitron.org.uk/forum/index.php/topic,12943.0.html) and due to the limitations of the PLC that I am using (It was free) I need to build a frequency to voltage interface board.
I would like to convert frequency to voltage, I am currently working with 50 Hz but could change this by modifying the shaft encoder. Assuming the target stays at 50 Hz I will need a 0 -10v signal that represents 40 60 Hz ideally, although 0 60 Hz would probably work all be it with lower resolution.
I appreciate that a simple integrator looking at the square frequency will work but if I use a cap big enough to limit the ripple to an acceptable level then the system is far to slow.
I probably need some sort of sample and hold circuit looking at each individual pulse width but really dont know where to start.
Any input would be greatly appreciated.
( I have some analogue switch ICs, bought to multiplex the PLC inputs, if that helps at all. )
Thanks
Alistair