[FUN] Testing Performance of segments

[Stephen Mitschke]

How do I test performance in FF segments. How do I know that my segments aretoo overloaded or hampering speed and performance.I was looking at the diagnostics of an installed Delta V system, but it willtake a long time to analyze the segments this way.I would appreciate any suggestion or more effective way of doing this.Regards,Nola Ogar

[Stephen Mitschke]

F-R has a test procedure for verifying FF segments. I have three DVprojects under construction and we have spent a month testing and fixingwiring problems in the segments. Puffer-Sweiven the local rep for F-R techdid an excellent job.THXRandy Marek (McDermott)----- Response 2 -----To assess segment performance in general and in particular for supportduring Factory Acceptance Testing we use the National Instruments NIBusmonitor. This provides you with more insight and understanding on what ishappening on the segment.Suppliers are not always happy if you work with the tool as it provides muchmore information than what is revealed with their build-in functionality.Before using this tool you might need some training.Peter Eigenraam (Shell Global SOlutions)

[Stephen Mitschke]

Hi Nola,As already mentioned, you can try using a 3rd party tool like a Bus Monitor(National Instruments, Softing and Smar have tools). These tools will giveyou an idea of loading on a running segment. Trying to "predict" what the loading on an FF segment will be is ratherdifficult. FF uses variable sized messages (from 8 bytes to 120 bytes) anddepends on the configuration. Some of the "things" that must be consideredto predict bandwidth include; how many devices, how many and type offunction blocks, what are the communication speed settings (Data Linksettings), how often you "read" a view in device, publisher/subscribercommunications, etc.FF is a VERY flexible and dynamic communication protocol. You can do morewith FF than any other communication protocol out there. Trying to"optimize" a segment takes knowledge. Most host systems out there will tryto "optimize" based on assumptions, but these assumptions may not always bein your (the user) best interest. The easiest way to optimize communicationsis by configuring segment layout based on a set of rules (For starters takea look at the FUN list's Installation Guide). These rules will typicallykeep you out of trouble with plenty of bandwidth left. There are other tools (and people) available that can help figure out theloading of a segment offline. These tools (typically spreadsheet based) areused to calculate what the loading would be based on user input (seepredicting above). The sad part about the "offline" tools I am aware of, arethat they are NOT user friendly. i.e. You need to have a great deal ofknowledge of what "goes in" to the fields. At one time, Honeywell had one ofthese spreadsheet tools available on their web site, but I can't locate ittoday. Best Regards,Kurt ZechDirectorKI Engineering

[Stephen Mitschke]

Dear Nola,The Syscon configuration tool in Smar's SYSTEM302 gives you an indication ofwhat the macrocycle will be at the time you are entering the configuration(offline). You can also verify the actual H1 macrocycle from parameters inthe transducer block of the HSE linking device.See also page 346 of the book "Fieldbuses for Process Control: Engineering,Operation, and Maintenance" (buy online in hardcopy or download immediatelyin softcopy). If your email does not support this hyperlink featurecorrectly, please copy the URL and paste it into your Internet browser. Mindthe line wrap, make sure to get the complete path all the way to the 3036:http://www.isa.org/Template.cfm?Section=Shop_ISA&Template=/Ecommerce/ProductDisplay.cfm&ProductID=3036Jonas Berge, Smar