Hi, I need some help for rescaling 0-10VDC to 10-0VDC modulating signal. for example: input 0VDC =Output 10VDC, 1VDC=9 VDC, 2VDC=8VDC...... 9VDC=1 VDC, 10VDC=0 VDC.

Could anyone help me to build a circuit for this? I can provide 24VAC or DC from external source.

 

hi c89,
Which type of OPA's do you have available?
E

 

With 24V DC available, you can do it with an LM324/LM358 (about the only thing an LM324/LM358 is good for).
Bias the non-inverting input to 5V with a voltage reference (do you have 5V elsewhere in the circuit you could use as the reference?)
Resistor between output and inverting input (any value between 4.7k and 100k)
Same value resistor between 0-10V signal and inverting input.

 

As I am very new to this, could you please provide me a circuit diagram for the same?

With 24V DC available, you can do it with an LM324/LM358 (about the only thing an LM324/LM358 is good for).
Bias the non-inverting input to 5V with a voltage reference (do you have 5V elsewhere in the circuit you could use as the reference?)
Resistor between output and inverting input (any value between 4.7k and 100k)
Same value resistor between 0-10V signal and inverting input.

 

As I am very new to this, could you please provide me a circuit diagram for the same?

 

Below is the LTspice sim of Ian0's circuit with a resistor network to generate the 5V bias to the plus input:
Note that since the the LM324 is a bipolar device with a PNP pulling the output low (top circuit), it doesn't go much below 1V minimum (yellow trace) due to the load from the feedback resistor.

To go to 0V output, you need an op amp (such as CMOS types, bottom circuit) that can pull the output to ground (red trace).

 

To go to 0V output, you need an op amp (such as CMOS types, bottom circuit) that can pull the output to ground (red trace).

Yeah, that is my question back to the TS - How close to 0.000 V does the translated output signal have to be? Can you give us more information about what is downstream / what the output is driving?

ak

 

LM324 has a low current NPN transistor in parallel with a PNP on the low-side of the output. It can pull down quite close to zero, but with rather limited current (50uA). 0-10V inputs tend to have a pulldown resistor, which give it a helping hand.