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Howto read 0-14V with PC?

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zanor

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Does anyone know how to read voltage(0-14V DC) with any port on a PC? I just need some schematics, I'm programming the program to read the port myself..
 

mengghee

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I think u can use an anolog to digital converter to convert the signal to a digital signal and connect it via any port ... parallel port perhaps ... don't really have schematic though. hope this helps.


regards,
mengghee
 

mengghee

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zanor,

i don't really have experience with adc, i have just come across it during my project in college long time ago. i noticed that in the datasheet from the link u provided does not have an application schematic. sometimes datasheet has application schematic which may ease u in designing.

regards,
mengghee
 

zanor

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okey..
I found another one, https://www.elfa.se/pdf/73/730/07306719.pdf
I think I will go for this one, there's just one thing I don't understand. On page 15 there's a schema for the inputs, but are this internal in the chip or is this someting I have to do for each of the inputs?
 

philba

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You didn;t say whether you want to use a parallel port, serial or USB. There is a bit of hardware that you will need to build. Google has many many hits for "adc pc circuit"

for a 5V ADC, you can use a voltage divider to bring the 0-14V down to 0-5V and then when you read a value from the ADC, just remember that the largest value (255 for an 8bit one) is 14V
 

zanor

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philba said:
You didn;t say whether you want to use a parallel port, serial or USB. There is a bit of hardware that you will need to build. Google has many many hits for "adc pc circuit"

for a 5V ADC, you can use a voltage divider to bring the 0-14V down to 0-5V and then when you read a value from the ADC, just remember that the largest value (255 for an 8bit one) is 14V
It will be either serial or paralell, That's the easiest. I think..
The last one I posted is an 12 bit a/d..
Yes, I was also thinking of an voltage divider, but I did'nt quit understand what they ment on page 15 on the last one.
 

philba

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there's a lot on P15, i have no idea what you are refering to..

If you are going to use the ADC78H90, then I'd use the parallel port and the SPI interface. google SPI to learn more about it. Needs 4 pins from the PC - 3 out, 1 in.
 

xjackal

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and u have to write a software for visulisation.thats something like oscilloscope.please look at my older posts in pc interfacing section.
 

silvio

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zanor said:
okey..
I found another one, h**p://www.elfa.se/pdf/73/730/07306719.pdf
I think I will go for this one, there's just one thing I don't understand. On page 15 there's a schema for the inputs, but are this internal in the chip or is this someting I have to do for each of the inputs?

It's clearly stated in datasheet:

An equivalent circuit for one of the ADC78H90’s input channels
is shown in Figure 6.
The capacitor C1 in Figure 6 has a typical value of 3 pF, and
is mainly the package pin capacitance. Resistor R1 is the on
resistance of the multiplexer and track / hold switch, and is
typically 500 ohms. Capacitor C2 is the ADC78H90 sampling
capacitor, and is typically 30 pF.

Hence all are internal, you don't have to provide them external.
 

zanor

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silvio said:
zanor said:
okey..
I found another one, h**p://www.elfa.se/pdf/73/730/07306719.pdf
I think I will go for this one, there's just one thing I don't understand. On page 15 there's a schema for the inputs, but are this internal in the chip or is this someting I have to do for each of the inputs?

It's clearly stated in datasheet:

An equivalent circuit for one of the ADC78H90’s input channels
is shown in Figure 6.
The capacitor C1 in Figure 6 has a typical value of 3 pF, and
is mainly the package pin capacitance. Resistor R1 is the on
resistance of the multiplexer and track / hold switch, and is
typically 500 ohms. Capacitor C2 is the ADC78H90 sampling
capacitor, and is typically 30 pF.

Hence all are internal, you don't have to provide them external.

Thank you! That was what I was hoping for :)
 

niket_304

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use a adc & give the o/p on a parallel port. read th eport using vb6. & make a look up table for the same.
 

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