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ADS131E08: Safety compliant

Part Number: ADS131E08
Other Parts Discussed in Thread: ADS1260

Hi,

Please clarify below queries,

1. What is the calculation of Rsense? I want to use ADS131E08 For to sense 0 to 120mA. What is the resistor value i can use?

2.By using this IC shall we acheive SIL3 safety certification?

3. shall we design 2 wire,3 wire sink and source, 4 wire configuration for 4-20 mA by using this IC?

4. Whether This IC support HART ? Iam plan to use DAC8742HPBS external PHY which will connect to IN_P pins. Is this will work?

Kindly consider this as urgent and reply

Warm regards,

Monisha OM

  • Hello Monisha,

    Thank you for your post.

    The absolute voltage on each input pin is limited by the analog supplies, AVDD and AVSS. You can find the Absolute Maximum Ratings in section 7.1 of the data sheet. In addition, you must also adhere to the input common-mode and differential input voltage restrictions listed in section 7.3. This will help you to size the sense resistor value to measure up to 120 mA of current.

    SIL ratings are system level specifications. You will need to certify the ADS131E08 in a complete system design with its surrounding circuitry.

    The ADS131E08 does not have any HART-specific features integrated, but the data rates and filter bandwidths are capable of measuring the frequency-shift keying (FSK) frequencies of 1.2 kHz and 2.2 kHz used in HART applications.

    Regards,

    Ryan

  • Hi Ryan,

    While connecting DAC8742HPBS HART IN/OUT connect to analog input channels, is it possible to implement hart?

    Also the SPI interface support daisy chain? (As we want to use more ADS131E08. But SPI count from MCU is limited)

     

    Warm regards,

    Monisha oM

  • Hi Monisha,

    Yes, the ADS131E08 supports daisy-chain configurations.

    May I ask why you chose the ADS131E08? Do you require simultaneous sampling?

    I realize now that you may not be trying to decode the FSK signals with our device, but rather measure the 4-20mA loop current. Depending on your requirements, you might consider using an alternative delta-sigma device, such as our ADS1260. 

    https://www.ti.com/tool/TIDA-060020

    Regards,

    Ryan