Answer / carl_ellis

1) How do you know that the device talks HART? Many field transmitters talk Brain, Honeywell DE, Foundation Fieldbus, Profibus or 4-20mA only.

Have you confirmed the HART functionality on that device?

2) Point-to-point (communicator-to-transmitter) is usually done with the device at address 0 and with the communicator polling address 0.
Is the communicator polling address 0?
Is the device at address 0?

3) On many transmitters, HART can be disabled. Is HART enabled on this transmitter?

4) The transmitter has to be powered, initialized and in its operating mode in order to communicate via HART. Sometimes transmitters are not powered, but when connecting from the a marshalling panel, it is obvious, because the transmitter is remote location. Is the transmitter powered and operating?

5) Are connections across the dropping resistor or across the transmitter's (+) or (-) terminals? Connecting across a pressure transmitter's 'test' terminals will not work properly for HART communication.

6) A loop isolator module that is not specifically designed for HART will strip off the HART signal, but pass the 4-20mA current signal. If a loop isolator is installed in the loop, is it designed for HART operation.

7) If the power supply ripple and noise exceeds the HART specification, the power supply noise will interfere with HART or prevent communication entirely.

8) The 475 can have 3 terminals at the top where the banana plug field cable plugs in. 2 terminals are for HART, 2 terminals are for Foundation Fieldbus (FF). If the cable is plugged into the 2 terminals for FF, HART communications will be blocked by not having a cable in the correct port.

Carl Ellis
Measure First

In which principle Woodward Governor 505 work in power plant? What are the input of Woodward governor 505

1 Answers  

---

how to define range of dp level xmeter in open tank

1 Answers  

---

Basics Instrumentation Question

1 Answers   Advantek Fuel Systems,

---

How to convert mmWc(mili meter water colam) to tph(ton per hour)?

0 Answers  

---

how u calibrate pneumatic n motorized c/v?

0 Answers  

---

---

How much voltage we get between two wire of 4 to 20 ma output? Is this voltage up or down respectvice to 4 - 20 ma ?

9 Answers  

---

What safety precautions you will adopt to work on Steam service control valve?

1 Answers   QAFCO,

---

why we set -10 volt in vibration sensor output,why not +10 volt

3 Answers   Sabic, TVS,

---

I have got a call of IOCL interview for projects having 2yrs experience. What sort of questions should I expect in the interview?

0 Answers   IOCL,

---

1.Give example of analog and digital signal 2. What is yhe advantage of 8086 than 8085

5 Answers   Bhel, College School Exams Tests, Profitec,

---

HOW DPT WORKS?

6 Answers   Essar,

---

how will do square root transmitter calibration

2 Answers   Roche,

---