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ADC131E0x Status Info Interpretation

Other Parts Discussed in Thread: ADS131E06

Hi,

try to understand the Status info of the ADS131E0x, but ...

What do I do: I use a ADS131E06, so 6 channels available. This implies, that 2 bits of FAULT_STAT_P and two bits of FAULT_STAT_N are don't care. Unfortunately I didn't found any note about that, so should this bits 0 or 1 ???

My guess is 0 cause a channel not there couldn't generate a fault.

I use following Input mux Settings for the first tests:

Channel 0:  Short

Channel 1: MVDD

Channel 2: MVDD

Channel 3: Short

Channel 4: Input (there is a small filter/protection circuit, but no Signal)

Channel 5: chip temperature

I read the three Status Bytes as C0 03 FA

==> C is correct, see Manual. A is correct cause I wrote this value into the GPIO Register.

Fault-Stat_P is all 0, ok, no channel overdrives the Input range and the two bits for the channels not present read as 0s, a channel which isn't there shouldn't generate a fault ..

Fault_Stat_N is 0011 1111: Channel 0 within Limits, ok. Channel 1 within Limits, ok. Channel 2 out of Limit ??? Here Vdd/4 is present, as the Manual told me. Ok, maybe we do single ended measurement, so the negative Input is tied to ground. But hey, measuring the analog supply with channel 1 should show same behaviour, if that is true, but didn't. Strange.

Channel 3 is short, same as channel 0. But different Status Infos???

Channel 4 is temperature, here the N Input is tied to a Diode, so it defenitly isn't tied to ground, isn't it. Also 1, which denotes fault??

Ok, Otherway round: As there is no info which bit corresponds to which channel, lets reverse the info.

Channel 6 and 7 (not present on my chip) reads 0, no fault. All other Show a fault. Ok, maybe short means shorted to ground not just connecting P and N. Now the two shorted Inputs Show the same Status. The both channels measuring the supply Show also 1, ok tied to ground. But temperature also Shows 1 ??? There should be a Diode between N and ground ???

And yes, the data I read on all of the channels is correct, I get correct values for the shorted Inputs (~130µV), correct values for the supplies and a correct temperature reading. So no channel is powered down or what ever Problems can arise.

The gain of the PGA for all channels is 1

Please tell me, how to interprete the Status info. Which bit corresponds to which channel and why is the pattern as it is for my Input mux Settings.

Thanks a lot.

With best regards

Gerhard

  • Hey Gerhard,

    Your interpretation of the given bits are correct. However, the fault detection feature only works when the inputs are taken external to the device. This is because the comparator input that detects a low or high voltage at the inputs is taken before the input multiplexer. When you use a setting other than "normal input" the comparator is connected to a floating node. I'd recommend trying this test with real voltages connected to the inputs using a bench supply and see if you can get it to work.

    Regards,
    Brian Pisani
  • Gerhard,
    Were you able to resolve this?
    ~Leonard