17VDC will have a 2200uf Filter cap with 100nf bypassing.

Wouldn't a 100uf cap decrease the ADC response time ?

Speaking of high frequency filtering, the project does use a GSM transmitter to send SMS during a fault condition. It is placed close to the controller.
Is it a concern ?

 

Can I finalize this ?

Yes, but I'd make the changes @crutschow suggested in post #20.

 

Like this ?

1. Like I asked, will it not effect ADC value update as the cap will be charged ?
2. Is a GSM/GPRS unit in close proximity an issue ?

 

Could we see the data sheet on the sensor?

 

I would love to have that but I do not have the sensor. I need to get that from the customer.
All he said was 9-28V, 4 -20 mA Pressure sensor.
I guess I need to get my hands on one.
He said it is the type that are readily available and has 2 wires.
I did see the sensor, I did see 2 wires and 4-20mA written on it.

 

Like this ?

Yup. Looks good to me!

1. Like I asked, will it not effect ADC value update as the cap will be charged ?

Ummm... unsure what you mean by that. Clarify? (R2, R3 and the capacitors make a low-pass filter with a cutoff frequency of 0.8 Hz. If that's too low you can just make the 100 uF capacitor smaller.)

2. Is a GSM/GPRS unit in close proximity an issue ?

I think that mostly depends on how the Arduino is affected, if at all. As far as this circuit is concerned, I don't think it matters.

 

I am PIC Guy.

Effecting ADC means , will the cap discharge fast enough for the ADC to register a value. It won't help if the Display response is slow compared to the actual pressure discharge.

I do not think the PIC will be affected with GSM transmitter.

 

The electronics will work just fine and the display will update faster than your eyes/brain can follow if you want it to.

 

Effecting ADC means , will the cap discharge fast enough for the ADC to register a value. It won't help if the Display response is slow compared to the actual pressure discharge.

Those R and C values create a filter with a 200 millisecond time constant, so I doubt anyone looking at the display will notice any slowdown or lag. And as I said, if you want it to respond faster just reduce the 100 uF capacitor to something smaller.

 

How fast do you expect the pressure to change?

 

200ms is good enough...
I thought it would be more than 500ms.

Thank you all.
Regards

 

The Circuit is built and Sensor connected.
With 250R it produced 1V as calculated and change is fast.
Customer said the Max pressure will be 5 bar which is 2.5V since it is a 0-10 bar Sensor.
I am thinking of putting a 5.1V Zener across ADC Pin to protect it further.
I believe it won't matter since the ADC will never come close to 5V.
What do you say guys ?

 

I am thinking of putting a 5.1V Zener across ADC Pin to protect it further.
I believe it won't matter since the ADC will never come close to 5V.

I recommend you NOT do that. See post #13.

 

I think you wasting your time and money.

4 - 20ma to 0 - 5 VDC converter board. ~$7 including shipping.
http://www.ebay.com/itm/like/361652368093?lpid=82&chn=ps&ul_noapp=true

 

I recommend you NOT do that. See post #13.

Thanks...I won't. Why asking help if I am not following, right ?

I think you wasting your time and money.

4 - 20ma to 0 - 5 VDC converter board. ~$7 including shipping.
http://www.ebay.com/itm/like/361652368093?lpid=82&chn=ps&ul_noapp=true

Not an option.