rob_croxford
- Aug 3, 2010
- 262
- Joined
- Aug 3, 2010
- Messages
- 262
Hi all,
I have been working on this one for a while... basically the problem is as follows:
I have a mainly analouge circuit that takes a variable 0-10V DC input and creates a linearly increaseing (frequency) square wave. This square wave is used to trigger the gate pin on a thyristor (through an optical isolator) which is used as a switch to control an electronic heater. The entire project works as a proportional controller for a heating system.
I have converted the variable DC input into a square wave by using a Voltage follower a MUX and a Comparator. (i can include a circuit diagram of this if it is needed)
So,
I have recently been trying to figure out a way of converting this process to a digital system. Unfortunatly Digital electronics is not my strong point.
My question is: Does anybody have any idea of how i can create a linearly increasing square wave (frequency) from a 0-10V variable DC input. Or can anyone give me a nudge in the right direction for a solution to this.
I have tried using a 555 timer however it is not reliable where linearity is concerned. I have also looked into using a Volt/Freq converter IC however they are to expensive.
Any help would be greatly appreciated.
Cheers,
Rob
I have been working on this one for a while... basically the problem is as follows:
I have a mainly analouge circuit that takes a variable 0-10V DC input and creates a linearly increaseing (frequency) square wave. This square wave is used to trigger the gate pin on a thyristor (through an optical isolator) which is used as a switch to control an electronic heater. The entire project works as a proportional controller for a heating system.
I have converted the variable DC input into a square wave by using a Voltage follower a MUX and a Comparator. (i can include a circuit diagram of this if it is needed)
So,
I have recently been trying to figure out a way of converting this process to a digital system. Unfortunatly Digital electronics is not my strong point.
My question is: Does anybody have any idea of how i can create a linearly increasing square wave (frequency) from a 0-10V variable DC input. Or can anyone give me a nudge in the right direction for a solution to this.
I have tried using a 555 timer however it is not reliable where linearity is concerned. I have also looked into using a Volt/Freq converter IC however they are to expensive.
Any help would be greatly appreciated.
Cheers,
Rob