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Hart 475 not Communicating Fisher DVC 2000
Hart communicator 475 not communicating with DVC 2000 fisher FIELDVUE.

Hi All

I facing problem in communicating HART 475 with DVC 2000 Fisher FIELDVUE. When I connect online, HART say no device found. Protection mode is also off from DVC.

DD files are also installed in hart.

Please help.

1 out of 1 members thought this post was helpful...

I'd suggest that you go through Jonas Berge's "New Tips and Tricks to get Value out of HART" because it is the most comprehensive compilation of HART user information on the planet and work your way through it.

https://www.linkedin.com/pulse/new-tips-tricks-get-value-out-hart-jonas-berge/

I'd suggest that you confirm that the 475 works (can connect to) on another device first, then confirm that the DVC is functional (has sufficient loop power/DC voltage).

It could be something simple, like a 475 that talks Foundation Fieldbus and you're connected to the wrong terminals. Or it could be more involved.

I have tried with valve link in communicator 475 application; still getting the same error no device found. Also I installed 250 resistance in the loop. 475 working on other transmitter. I have tried on three dvc 2000 but still getting the same error. :(

Still facing same issue.

Please help.

You haven't listed out the things you've tried and what you've ruled out through troubleshooting. There are so many things that can cause a HART attack, that I'll just print Mr. Berge's
- list of things you might not know about HART
- List of design issues that can cause a HART attack

--- from Jonas Berge's New Tips and Tricks to get Value out of HART ---

You may have used 4-20 mA/HART for more than 20 years and think you know everything about HART. However, having visited and helped many plants and tracked various social media channels for many years I have noticed there are many misconceptions. These misunderstandings are part of the reason why in the end HART goes underutilized. For instance you may not know:

* Resistor need not be exactly 250 ohm for the sake of HART

* Smart valve positioner does not need resistor
* Some control systems are affected by the HART signal and need an input filter

* Some control systems affect the HART signal and need an output filter

* When a Partial Stroke Testing (PST) device is connected in parallel with a solenoid valve you need a HART line conditioner

* Cables have special capacitance requirements

* If the line is noisy 4-20 mA works but HART does not

* Max loop resistance is 600 ohm which limits series devices

You cannot connect DCS, handheld field communicator, wireless adapter, and smart signal conditioner all at the same time due to master conflict

* HART5 systems do not support HART7 devices

* HART5 devices have the same diagnostics as HART7 devices

* Some devices can be configured to operate as HART5 or HART7

* Depending on if the device is configured to operate as HART5 or HART7 it will need a different DD file

* A HART input filter is not the same as a HART output filter

* The triggered burst mode and event notification (sometimes referred to as report by exception) functions are intended for WirelessHART not for 4-20 mA/HART

* You can get 4-20 mA without a DD file but you cannot configure the sensor type and other settings

* If the loop resistance is too high, 4-20 mA may still work but HART may not communicate

* HART compliant safety barriers are required

Some of the mistakes in physical network design that prevent HART from working properly include:

* Analog I/O cards in the control system or RTU chosen not supporting HART communication pass-through

* The 4-20 mA cable chosen does not meet HART communication requirements with regards to capacitance and shielding

* Too many devices in series in the design result in excessive 4-20 mA loop resistance and voltage drop, allowing 4-20 mA to work but not HART communication

* Cable too long

* The safety barriers chosen are not HART compliant

* The 4-20 mA cabling route planned too close to power cables resulting in noise pickup allowing 4-20 mA to work but not HART communication

* Cable shield connection not included in wiring diagrams and therefore not maintained all the way from the device through the junction box to the control system I/O

* Device housing grounding not including in wiring diagrams and therefore not done

* Cable shield grounding not included in wiring diagram and therefore not done correctly

* The control system analog inputs are affected by HART communication yet HART input filters are missing in the design

* The control system analog outputs are affecting the HART communication yet HART output filters are missing in the design

* Partial Stroke Testing (PST) device is connected in parallel with a solenoid valves for the Emergency Shutdown (ESD) valves yet HART line conditioners are missing in the design

* 250 ohm resistor in valve positioner current loop design result in insufficient compliance voltage

* The field device chosen is not HART compliant

* The field device chosen does not have a DD file

* Noisy DC power supply

----- End -----

His list omits obvious things, like
- The transmitter/loop has to be powered (the handheld does not power the loop)

- The handheld/PC-modem (HART master) has be functional

- HART master has to be addressing the same address as the HART device (default address is typically address 0 for point-to-point communication)

The list mentions I/S barrier HART compatibility. Other devices in series in the loop, like a loop powered indicator or a 4-20mA isolator/repeater, can strip HART off the 4-20mA signal, unless designed for HART pass through.

The remainder of his app note covers these points in much greater detail.

Note the issue: 250 ohm resistor in valve positioner current loop design result in insufficient compliance voltage.