what wiring checks are required?

[jkealey]

For a new contruction FB installation, what wiring checks would you recommend the Construction Contractor perform?

Should the wiring be "rung out" (continuity check)?
Should a FB "communication analyzer" be used before the devices are connected? (what would be communicating?)
Or, can you just power up the segment and hook up the instruments and let the system diagnostics check the segment out?

[sheusel]

For a new contruction FB installation, what wiring checks would you recommend the Construction Contractor perform?

Should the wiring be "rung out" (continuity check)?
Should a FB "communication analyzer" be used before the devices are connected? (what would be communicating?)
Or, can you just power up the segment and hook up the instruments and let the system diagnostics check the segment out?

Dear Jkealey,

system diagnostics will not be able to tell you if the segment is wired correctly.
If a device does not have power, it will not show up in the communication and therefore cannot be analysed by your host.
I don't think that you need to do any tests with a communication analyzer before there actually are any problems.
A basic test should be done after the wiring:
- does every device have power?
- does the host have power?
- are all connections made correctly (check screw terminals)

After this you should be able to diagnose any further problems with the diagnostics of your host.
Under lab conditions a communication analyzer is not necessary - all communication tests can be performed with an oscilloscope.
A small portable analyzer might be of some use in the field although the information it will provide is of a general nature.
You will not be able to solve a communication failure due to e.g. different
firmware revision with a communication analyzer.

If you have further questions, please feel free to contact me directly.

Best regards / mit freundlichen Grüßen

Stefan Heusel

Technical Support Manager Bus Systems
Process Automation Division

Pepperl+Fuchs GmbH
Koenigsberger Allee 87
D-68307 MANNHEIM
Phone: +49 621 776-1299
Directfax: +49 621 776-27 1299
Department Fax: +49 621 776-1429
E-Mail: sheusel@de.pepperl-fuchs.com
www.pepperl-fuchs.com

Signals for the world of automation

[Peter]

For a new contruction FB installation, what wiring checks would you recommend the Construction Contractor perform?

Should the wiring be "rung out" (continuity check)?
Should a FB "communication analyzer" be used before the devices are connected? (what would be communicating?)
Or, can you just power up the segment and hook up the instruments and let the system diagnostics check the segment out?

You may wish to consider the range of the Relcom Fieldbus monitors supplied by MTL. One of the units, the FBT-5, is a FB wiring validator. It's battery powered (auto shut off), and is intended for use with the FBT-3 Monitor. The FBT-5 acts as a signal generator, providing dc power and a simulated FB signal. The FBT-3 takes power, signal and noise measurements.

Peter Inns, MTL Australia

[jomalley]

The construction contractor should ring out the spurs on the segment from the device location to the H1 termination. The construction contractor should also verify all wire tags, terminators and verify the wire color code (+/-), you don’t want crossed signal wires. This way the construction contractor has verified all the wire is in the right place.



Once the above is done, the construction contractor should terminate the devices, again verifying the color code to each device. Each step should be recorded in the construction documentation, sign offs, etc…. Then the system should be sold to the commissioning group, this should be a formal punch turnover.



When the above is done, the commissioning group should light up the devices and verify the devices with, decade box, pressure check, etc… Again this should be recorded on the commissioning documentation that has been organized in the “Loop Folder”. If a device does not work, the commissioning team would go through the normal verification process, continuity check, voltage, terminator check, etc…. The commissioning team should allow the client to verity their work, but if the client is not “On Demand” the loop/spur should be considered sold without client verification, waiting for the client can eat up enormous amounts of time.



If the normal testing does not fix the problem, it may require further investigation. But this should not be the norm.

[dhobart]

Have you resolved your contractor fieldbus testing procedures as yet? The EUAC's System Engineering Guidelines, AG-181, is a good starting point. This document is available online, at no cost, from the Foundation's website.

Testing of fieldbus cables is different but easier than conventional 4-20 ma systems. The Relcom FBT-3 is an invaluable tool. You will want that as a minimum. Also you may want a Fluke 190 Series recording scope, a capacitance meter, etc.

I recently put together some factory and site test procedures for a training program. Please contact me directly if you are still interested.

David Hobart, P.Eng
Senior Associate and Principal
Sterling Valley Associates
Instrumentation & Controls
Engineering and Construction Management

Tel: 802-253-4634
Cell: 802-249-1840
Email: dgh@SterlingValley.com

[Heather Santos]

Another FF document AG-163 r2.0 might be useful for installations, it is the Application Guide for I.S. Installations.

More info:

http://fieldbus.org/News/default.asp?news_x_language_id=420

http://www.fieldbus.org/about/foundationtech/resources/

[tibor]

All of the aboves are fine proposals. Finally let me offer another one. Very useful from my point of view...

http://www.deak.hu/download/troubleshooting_guide.pdf

Tibor FARKAS
D.E.A.K. Process Control Ltd.
P+F; Metso agent
Hungary
Tel.: +36 25 507 815
Mobile: +36 30 389 87 44

[jberge]

A communication analyzer is only helpful after devices have been connected as it monitors the communication between devices.

Have you looked at the book "Fieldbuses for Process Control: Engineering, Operation, and Maintenance" (buy online in hardcopy or download immediately in softcopy):
http://www.isa.org/fieldbuses
Chapter 3 of gives some guidelines on commissioning, such as "ringing out" but using the FF "live list" instead of two guys with walkie-talkie.

If you indeed have trouble, refer to chapter 6.