DC voltage sensor (range 0-100V)

[shaneelal]

voltage sensor site:www.edaboard.com -search

I"m building a device that senses both current and voltage and displays result. I"m using a PIC18F452.I"m supposed to sense the current and voltage every 2sec
Should I use two channels on the PIC,one for each sensor to perform ADC? Or should I use an analogue multilpexer?
I"m looking for a dc voltage sensor which can sense atleast 0-50V,prefferably one that has a range of 0-100V .
Specifications required:

Voltage Range 0 - 100 volts
Relative Precision of Range ±1%
Max Linearity Error ± 0.5 % of reading
Band Width at ±1db 2.5 Khz

The one I'm looking for is found in this device Micro ADM™ Micro Arc Data Monitor.
Website - **broken link removed**

manual at https://www.cweldtech.com/Manuals/MicroAdm-Manual.pdf

Does anyone know the sensor they used or a similiar one?
Your help will be greatly appreciated.

 

[IanP]

Re: DC voltage sensor

As DC voltage sensor you can use a standard A/D converter and to cover 0-100V @ 1% range you can use 10-bit internal ADC from PIC.
To connect 100V dc to PIC you will need a 1:20 voltage devider followed by a buffer.

 

[shaneelal]

Re: DC voltage sensor

Could u tell me what kind of circuitry would I need for a 1:20 voltage divider and a buffer? What value resistors should I use? I have an idea,but just need to be sure. Thanks for your help.
If anyone knows of a sensor like this please tell me.

 

[IanP]

Re: DC voltage sensor

Use voltage devider formula:
Uout=Uin*R2/(R1+R2)
where R1 is connected to the voltage source, R2 between R1 and 0V and output is taken from R2.
For example, if you say that R2=10kΩ then R1=190kΩ .. (Uin/Uout=1/20)
Use good instrumentation amplifier as a buffer. To select on go to Analog Devices web site. For some of their products they offer free samples ..

 

[bobcat1]

Re: DC voltage sensor

Hello

Use TI INA138 current to voltage converter for sampling the current flow

It's gain programmable and easy to use


All the best



Bobi

 

[smartsarath2003]

Re: DC voltage sensor

Use good instrumentation amplifier as a buffer

Hello IanP,
What are the consequences if the voltage devider is connected directly to ADC. I thought the ADC's built up of op-amp, which has high i/p impedance. So the ADC should pick up the scaled signal. isn't It?

 

[extradeath]

DC voltage sensor

You can use op-amps to make a voltage drop by using a certain scale....

For example you may arrange the op-amps resistance values such if it gives 5V output than the input was 100V as ful scale.... and so on

THis is done as an input A/D channel the can sense up to 5V and so on...

I you are interested please mail and I can send specific details ....

Don't hesitate....

 

[shaneelal]

Re: DC voltage sensor

extradeath,can u check ur pm for my email,i'll like to know the details

 

[extradeath]

DC voltage sensor

As soob as I can...