ADS1248: ADS1248IPWR – Is My 4-Wire Pressure Sensor Circuit Correct?

Michael Soldierram

Part Number: ADS1248

Tool/software:

Hi everyone,

I’m using an ADS1248IPWR to read a 4-wire, 4-20 mA pressure transmitter.

I am not sure about the accuracy of the pressure measuring circuit. I made a drawing like this using ADS1248. Could you check the deficiencies in the circuit or can I get results from this circuit ?

Thanks!

3 months ago

+1 Bryan Lizon86 3 months ago

TI__Guru 52576 points

Hi Michael Soldierram,

I pretty much already answered this question a few months back, and you did not take any of my advice: https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/1491837/ads1248-ads1248-drawing-problem-with-pt100-and-pressure-transmitter

No need to ask the same question twice

-Bryan

0 Michael Soldierram 3 months ago in reply to Bryan Lizon86

Prodigy 40 points

I am sorry for this, I guess I should use this function " "Ask a related question"

I made changes to the connection, is the connection correct?

0 Bryan Lizon86 3 months ago in reply to Michael Soldierram

TI__Guru 52576 points

Hi Michael Soldierram,

As I mentioned in my other post, I would put a pull-up resistor on RESET so the ADC starts in a known state

Also, you have REFOUT connected to ground. You just need to move the ground connection to the VREFCOM pin instead of VREFOUT and it should be fine

The resistors on the inputs are a little high value (5k, 6k), so you might get some offsets due to leakage currents. But you can always change this later. Related to this the cutoff frequency of your filters is pretty low (<300Hz for the RTD input), so watch out for settling issues when you start testing / troubleshooting your board

You also have no anti aliasing filter on your current input

-Bryan

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ADS1248: ADS1248IPWR – Is My 4-Wire Pressure Sensor Circuit Correct?