Hi,
I'm new to this forum, I know some digital electronics and I'm rather good at programming 8051 microcontrollers using assembly language, I'll be more than happy to help anyone if it's within my power. However, my knowledge of analog electronics leaves much to be desired.
My problem is this:
I want to heat a Nickel-Chrome wire to a temperature of around 750°C and keep that temperature constant as the wire is being used in a cutting application.
To do that, I only have two options:
1.- Monitor the wire's temp using an IR thermometer connected to a temperature controller. (rather expensive).
2.- Monitor the wire's resistance value (it increases as the temp goes up, check this page: http://www.heatersplus.com/nichrome.htm) and adjust the voltage accordingly (AC voltage) using a solid-state variac with an analog input until it reaches the desired resistive value, thereby also reaching the target temperature.
I have a hunch this has something to do with differential amplifiers, but how do I measure the wire's resistance while it's being being heated by an AC source? How would the circuit look like?
Any suggestions? or would some other approach be more practical?
More data on Nichrome 60 wire:
http://www.pelicanwire.com/alloyproperties.htm#n60
http://www.resistancewire.com/Html/Technical/CurrentTemp/CurrentTemp.php
Thanks
I'm new to this forum, I know some digital electronics and I'm rather good at programming 8051 microcontrollers using assembly language, I'll be more than happy to help anyone if it's within my power. However, my knowledge of analog electronics leaves much to be desired.
My problem is this:
I want to heat a Nickel-Chrome wire to a temperature of around 750°C and keep that temperature constant as the wire is being used in a cutting application.
To do that, I only have two options:
1.- Monitor the wire's temp using an IR thermometer connected to a temperature controller. (rather expensive).
2.- Monitor the wire's resistance value (it increases as the temp goes up, check this page: http://www.heatersplus.com/nichrome.htm) and adjust the voltage accordingly (AC voltage) using a solid-state variac with an analog input until it reaches the desired resistive value, thereby also reaching the target temperature.
I have a hunch this has something to do with differential amplifiers, but how do I measure the wire's resistance while it's being being heated by an AC source? How would the circuit look like?
Any suggestions? or would some other approach be more practical?
More data on Nichrome 60 wire:
http://www.pelicanwire.com/alloyproperties.htm#n60
http://www.resistancewire.com/Html/Technical/CurrentTemp/CurrentTemp.php
Thanks