[FUN] project execution with FF

[Stephen Mitschke]

I have a few questions about how Fieldbus affects the execution of capitalprojects.I work for an engineering firm that has not done a Fieldbus project yet, butmore and more of our proposals are asking about it. (background: We have standardized on INtools as our design tool and we doall our own system configuration work)1-Schedule: various presentations have emphasized that you must buy thefield devices with "all necessary function blocks". We are under tremendouspressure to get in-line devices purchased as quickly as possible onprojects. Does this mean we need to wait until we have the configuration ofevery loop figured out? How painful (procedure & price) is it to addfunction blocks after the PO is issued? After the device has been shipped?2-P&ID's: The articles I've seen say stick to normal P&ID symbology. Hasanyone had a Client (facility owner) who pushed for trying to show more ofthe implementation details on the P&ID's? 3- Complex Loops: Have the system configuration tools been sufficiently"self documenting" to meet the end users needs? Are supplemental documentsneeded?4- Datasheets: how much function block information have people put on thedatasheets? Just the fact that certain blocks exist in the device? All theparameter info? (I hope not)5-Segment Diagrams: INtools has the capability of doing them. Have Clients(facility owners) been satisfied with the default format?--------------------------------------------------------John Kealey, Instrumentation Dept.Mustang Engineering

[Stephen Mitschke]

Answer for 1 below:As long as the P&IDs are complete you can go ahead and plan the devices needed to implement the logic. There are also other ways to "design for the future" by using devices that support Function Block (FB) Instantiation (this is a method to "turn on" or off certain FB's in the device. Also, there is a way to upgrade/change device software in the field. Only certain device and host manufacturers support these features, so you must be very selective in the vendors used. The chances are that the devices and host will come from different vendors.We can help them out with this... been there, done that... It takes a different thought process to do this correctly tho...-Kurt Zech---- original -----> 1-Schedule: various presentations have emphasized that you must buy the> field devices with "all necessary function blocks". We are undertremendous> pressure to get in-line devices purchased as quickly as possible on> projects. Does this mean we need to wait until we have the configurationof> every loop figured out? How painful (procedure & price) is it to add> function blocks after the PO is issued? After the device has been shipped?

[Stephen Mitschke]

Be very careful here guys. Don't let finances and plant availabilitydictate your program. You will be learning 'on the job' and trying togenerate new strategies and commission whilst under pressure is not a niceplace to be.You need to review the types of function blocks available within each deviceas this changes from vendor to vendor. Plan your control strategy, reviewyour site standards for configuration and work your way from there. Decidewhere you want your logic to reside eg. in your field device, or in yourLinking Device or even in your SCADA tag database. Are you going to complywith your existing site policy on the location of configuration? Are yourexisting site policies still appropriate for foundation fieldbus? Fielddevices come with a preset number of function blocks and are not upgradable.This can cause problems if you decide you need a particular 'non-standard'function block at a later date so pick your vendor carefully.Bottom line - do your homework on function block availability. We arecurrently in a position that were are having to change out a device withlimited function blocks for a device with more function blocks to enable usto comply with the current site procedures.Have a look as to how your prospective system presents its strategy both onscreen and hard copy (for those 'old greys' that cant read from ascreen...). If you strategy printout contains good function blockinformation then it is sufficient to include only the types of functionblocks on your field device datasheet.JohnJOHN BAZLEYBeca Simons - Tauranga

[Stephen Mitschke]

I tend to agree with most of what John just posted and Kurt did a nice jobof responding to question 1 though, as usual, I have a bit more to add.1. No, you do not need to wait to have every loop figured out to order thedevices, but you do as John said need to have your control strategy, as wellas the items he mentions addressed. The Function Block issue is manufacturerspecific.2. P&ID's: Other than showing the interconnecting "wiring" differently, mostfolks are not doing anything different. ISA-5.1 is also leaning in thisdirection. Some folks are however showing multiple signal devices slightlydifferently. There is also a couple threads on this topic in the FUNarchives on the FF site.3. Self documentation should cover 90% of your requirements and I am surethis will only improve with time.4. Datasheets: Again samples are in the FUN archive though the most commonapproach is to indicate the block types available/required. Greater detailthan that is part of the configuration.5. Segment Diagrams: I have not heard differently, but perhaps the INtoolsmembers on this distribution list will comment as well.Ian Verhappen

[Stephen Mitschke]

Gentlemen,Being with INtools development team for quite a number of years I would like to comment that we have not heard complaints on the presentation side of the segment.INtools provides 2 types of drawings/deliverables for Fieldbus systems:1. Segment wiring drawings, wiring diagrams that present the wiring based on a complete segment, showing all connected instruments- some people would comment that this document is sufficient and there is no need to have individual loop drawings2. Fieldbus loop drawings- individual loop drawings for each and every loop, as for the classical instruments. The pro's arguments to this approach is that most plant commissioning are done on a loop basis and not per segment. Contractors need to commission a loop, making sure it works and are less interested to show the full segment operation as sometimes a loop can ( although not recommended) be split into more than one segmentMeir SteinSmartPlant Electrical Product ManagerIISDC - INtools

[Stephen Mitschke]

Dear Mr. Kealey,1. There are Fieldbus devices that have limited block capability,devices that have the blocks but require additional licensing for each andevery device, devices that have the blocks at no extra charge, and devicesthat have instantiable function blocks at no extra charge. Take anylicensingissues where applicable into account when budgeting. Since you wouldn't wantto delay your project by delaying device selection and purchasing, and youdo want to benefit from decentralized control, you need to select capabledevices early on in the project. Devices that have instantiable functionblocks provide the greatest flexibility. Instantiable means that the devicehas a large library of block types and a large memory for which many ofthese blocks can be chosen, i.e. many different kinds to chose from, and theability to have several of each type if required. I agree that by selectinginstruments with instantiable blocks there is a less pressing need to at thetime of purchase know exactly what block types you need in each particulardevice.If devices need special license to be added later to run blocks this will beadditional cost and administration for each device.As a consequence, select a second-generation system with a host thatsupports instantiable function blocks.Jonas Berge

[Stephen Mitschke]

I'm not sure I agree with the 100% of what's been said to date . . . here'smy $0.02 US:1.) In-line devices: Are you planning to do PID in field devices? If yes,get all your valve positioners with PID and AO. If not, get them with justAO. For Vortex shedding meters or Coriolis meters, get them with AI(several, at least two, for Coriolis) . . . if you do PID in field devices,do it in the valve. I suppose in some rare event you may have a flow that'sa cascade master, but these should be one-off's. (Someday soon I hope vendors figure out that they shouldn't be charging ashigh a premium for added function block capability.)Unless you're using Smar, I don't know of many vendors who support more thanrudimentary PID in field devices. By rudimentary I mean SISO, no constraintcontrol, no splitters, no cross-limiting, etc. Not that this can't be done,It just has to be done in the host . . . the PID can still reside in thefield device and you still get a measure of single-loop integrity, but whenthe host goes away (e.g., H1 card fails) you revert to simple PID. This ishow we're doing it; been running for almost 3 years now.If you're in a cold climate, maybe you'll want another AI for casetemperature. Or maybe you'll get that "free" with your system's diagnosticcapability.2.) If your client wants to show nuances of control wiring on P&IDs then Ipity you. Why don't we show what card and controller they're connected toalso? We use ordinary P&ID's. I could be persuaded to show functions sharedin a single device (contiguous balloons) but this is really nothing new (hadthis before FF).3.) The ones I use (on Emerson DeltaV) are sufficient for documentingcontrol strategies. Better back them up though, as all MS Windows devicesare susceptible to virus attack and other ills.4.) I would buy all the devices of a particular species (e.g., pressuretransmitters) with the same blocks. Just have a general note. If they're allthe same, then spare parts are the same and swapping them around is noissue.5.) Sorry haven't used Intools. However, we used segment drawings only. Whenloop checking or doing maintenance, we want to know what else is on asegment that we're working on. A traditional loop drawing would have to becustomized to show this. I'd say "save a tree", but we have the same # ofpieces of paper -- it's just the same drawing for all devices on a segment.Hope this helps,John RezabekBP BDO Manufacturing

[Stephen Mitschke]

IanThese folks may want to investigate using products that have maximizedthe free function blocks that are included with their products. Smardoes this quite well there Contact person is Barry Lundin @780-448-0319.Hopefully this information will be of some help to your budgetingfigures.Gary MattieShell Canada