• Comment on 2-wire 4-20mA transmitters: Controlling 2-Wire Transmitter Outputs with Externally Powered Sources (Part 4)

  

  Collin Wells

  Hello, The best way to keep systems with externally powered inputs functioning well is to isolate the input and create an "Input Isolated 2-wire Transmitter" type system. As mentioned in the line you quote, if you try to take an input signal…

  • over 2 years ago
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• Comment on 2-Wire 4-20mA Sensor Transmitters: Sensor and Transmitter Current Consumption Limitations (Part 3)

  

  Collin Wells

  Hello, I'm glad you enjoyed the blog series. With >200mA peak output current requirements I'm not sure you're going to be able to find a way to get your design to work on a 2-wire loop. Consider desiging a 3-wire or 4-wire sensor transmitter…

  • over 4 years ago
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• Comment on 2-Wire 4-20 mA Sensor Transmitters: Background and Compliance Voltage (Part 1)

  

  Collin Wells

  Hello Patrick, While in theory an idea like that may work, the actual implementation would violate the standards for 2-wire 4-20mA transmitters which require only two wires (Vloop, RTN) in the loop. Take a look at Part 4 which talks about a similar application…

  • over 8 years ago
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• Comment on 2-wire 4-20mA transmitters: Controlling 2-Wire Transmitter Outputs with Externally Powered Sources (Part 4)

  

  Collin Wells

  Hello Yilak, In figure 4 the sensor supply powers the sensor, MCU+ADC, and 1/2 of the digital isolator. The XTR116 VREG connection powers the other 1/2 of the digital isolator. The only cases where isolation is not required are those where the sensor…

  • over 6 years ago
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• Comment on 2-wire 4-20mA transmitters: Controlling 2-Wire Transmitter Outputs with Externally Powered Sources (Part 4)

  

  Collin Wells

  Hi Shibili, Figure 4 illustrates that isolation is required if the sensor/MCU GND has a voltage potential relationship to the VLoop GND (or is directly connected to Vloop GND). If it does, then shorting the sensor/MCU GND to the IRET pin will short IRET…

  • over 6 years ago
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• Comment on 2-wire 4-20mA transmitters: Controlling 2-Wire Transmitter Outputs with Externally Powered Sources (Part 4)

  

  Collin Wells

  Hello, This depends on if your application is to design a 2-wire or 3-wire transmitter. The XTR111 is used in 3-wire transmitter designs which are not discussed in this blog series but are discussed in some related blogs by my colleague Kevin Duke. You…

  • over 6 years ago
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• Comment on 2-Wire 4-20 mA Sensor Transmitters: Background and Compliance Voltage (Part 1)

  

  Collin Wells

  Hi Patrick, I suppose, but you're very likely to experience grounding or other issues because the XTR devices were not intended for use in this manner. Also, what you're describing sounds like a 4-wire transmitter which typically has separate supplies…

  • over 8 years ago
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• How to design cost-sensitive DC instrumentation circuits

  

  Collin Wells

  Other Parts Discussed in Post: TLV333 , TLV2333 , TLV4333 Many sensors produce low-level DC outputs that require a high input-impedance amplification stage to increase the signal amplitude. Sensors used in personal and portable electronics require operational…

  • over 6 years ago
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• How to minimize crosstalk in cable designs

  

  Collin Wells

  Winter is my favorite time to work on hobby projects in Texas. My garden is filled with easy-to-maintain winter or cover crops, and it’s cool enough to work outside without overheating. While working on a recent project, I had to re-route some…

  • over 9 years ago
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• How to design cost-sensitive battery-monitoring circuits

  

  Collin Wells

  Other Parts Discussed in Post: TLV369 , TLV379 In portable electronics designs, typical battery-monitoring systems measure battery voltage and battery current to detect when the battery needs charging or replacement. In this post, I’ll demonstrate battery…

  • over 6 years ago
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