LTC2400 SPI interface

[HenrikOlsson]

Hi,
I'm not following you on the resolution. You say the transducer measures 0-100000 PSI with a resolution of 0.0001 PSI? That's 1.000.000.000 "counts" across the 16mA output swing - WOW!

I mean, even at 1 PSI "per count" the difference in output current is 0.016/100000=0.16uA. Push that thru your 250ohm resistor and you get a voltage change of 40uV per PSI - that's not a lot.

If you mean 100PSI then it gets a little more managable as 1PSI now eqauls a change in current of 160uA and a voltage change across the resistor of 40mV.

/Henrik.

[PUGALENTHI.P]

Hi,
I'm not following you on the resolution. You say the transducer measures 0-100000 PSI with a resolution of 0.0001 PSI? That's 1.000.000.000 "counts" across the 16mA output swing - WOW!

I mean, even at 1 PSI "per count" the difference in output current is 0.016/100000=0.16uA. Push that thru your 250ohm resistor and you get a voltage change of 40uV per PSI - that's not a lot.

If you mean 100PSI then it gets a little more managable as 1PSI now eqauls a change in current of 160uA and a voltage change across the resistor of 40mV.

/Henrik.

THANKS FOR YOUR REPLY


Sorry, actually the circuit must support wide ranges of transduser so that for low range transduers like 0~100 mbar and mid range transdusers like 0~500 bar it must have 0.0000 resolution and for high pressure transdusers as i said before like 0~100,000 it must have the accuracy of 0.1% and no need to worry about the resolution. so the circuit must have the capability to measure as much as possible.but for now i used the over sampling method and i got the accuracy of 0.1% for 0~100,000 psi on 10 bit internal adc which is my first stepping stone with the valuable help from MR.Henrik and thanks a lot for that.

THANKS and REGARDS,
PUGAL.