Stephen Mitschke
August 12th, 2003, 12:35 PM
Attached is a JPEG file showing how we are proposing to do the new Segmentdrawings. One drawing for each H1 Segment and it is similar to what is beingproposed by Raja. If anyone else has ideas or comments please send them on.ThanksIan Verhappen<<Segment_dwg.jpg>> -----Original Message-----We are at the design stage of Foundation Fieldbus for our Causticisng Plant.Causticisng Plant is part of our 850 Tonne/day capacity Pulp Mill. Thereare about approx. 60 Instruments in the Causticising Plant FF system and weare planning to have four segments. We have chosen Smar system 308 as ourhost system. We would like to know whether to use the format of existingloop drawings, Field-----> Field JB-----> Marshalling Box------>DCS or isthere any better way of representing FF instruments on drawings. All ideasand suggestions are most welcome to my email address as shown below.RegardsRaja Lokuketagoda- - - - This was merely a sample and is actually VERY Close to what we did on theNRU. The reason to show the software on the loop drawings is that it wasdecided by S5.1 that it should NOT be on the P&ID. The segment/loop drawingrepresents how the segment is installed/configured and hence our reason forshowing this information here.In response to your second question about InTools. Yes, they will be able togenerate 'automatic' segment drawings from the database.IanIan VerhappenSyncrude Canada Ltd. MD 0032P 780/790-4079, F -5190, cell 799-6017verhappen.ian@syncrude.com-----Original Message-----Ian,I do not agree with the proposed drawing. I agree with the layout ofhaving a complete segment drawing with all associated instruments but dothink we should be showing the "software" components on this drawing.(Drawings are typically not updated with software changes and changingcontrol from the host to a field device can now be done quite easily.) A database holding this information would be a much better solution.(Would INtools be capable of holding this information in a methodthat the segment drawings would be automatically updated?)Sorry, I have been out of the loop on how UE-1 is handling some ofthese items.Are our "loop" drawings going to remain soft after UE-1, or willthey be transferred to Microstation?Mike Achtemichuk- - - -I am sure you have this covered but I could not resist to stick my nose intothis!The drawing of course does not show the terminators and power supply. SinceI know that you know this, I wonder how the tech's will know to be surethere is a terminator somewhere in the system. I assume the power isprovided from the FF interface card. The other quick question is thegrounding of the shield - where do you ground? Which end?Now, just some "nice things" to think about on the drawing -- power consumption for each device- A device that has a LAS but is not active, same with PID, etc.- total length of the segment = home run + each spur- Device address - maybe a blank to write it in later / after assignmentSorry to butt-in!Thanks for listening -Chuck- - - In response to one of Chuck's comments, the intent was to show theTerminator block differently than the expansion block, likely with a letterT or a light on the block. Any suggestions from the list on this or Chuck'sother suggestions?Ian- - - I would like to offer some of my thoughts on the content of a Segmentdrawing. I agree on one drawing for each H1 segment. The drawing shouldrepresent the physical aspects of the segment, for example, devices bytagname, power supplies/conditioners and their circuits, expansion andterminator blocks, host card, the type of the wiring used, approximatewiring distances, locations of the devices where practical. This wouldfacilitate troubleshooting on the segment as well as for making additions orother revisions. Most of this data is "static" in nature and will change infrequently, if atall. I would avoid putting more dynamic type of data such as calibrationsettings, model numbers, etc. on the segment drawing because these changemore frequently and then you would have one more document to worry aboutkeeping up to date. Most or all of this data is readily available from thehost system.Also, I would not call it a Loop Drawing. One segment can have several"traditional" loops on it. This way we can keep the terminology straight.Thanks,Gary Addison- - - Dear Ian,I agree with Gary Addison's approach.1. Instead of "loop drawing" or even "segment drawing" I would call ita"network drawing" since you would most likely make one drawing for theentire network (all that comes out of one communication port). E.g. anetwork for intrinsic safety may consist of one safe area segment and fourrepeating safety barriers with one hazardous area segment each, total offive segments connected to one interface port.2. Only "static" stuff. I.e. include hardware like a terminator butperhapsnot software like PID or Link Master functionality. E.g. you may shufflearound the blocks to execute elsewhere or even add blocks. When you replacedevices you may add or lose the link master capability etc. These softfunctions are already well documented by the configuration tools so youcould print out (or export to Excel) a cross-reference list of this fromthere and it will always be updated because you are automaticallydocumenting as you configure. If soft functions are included in a drawingmade in another software package there is a risk you forget to update it to"as built".3. I prefer the plain "host" term (from HSE spec. and ISO FMS) asopposed to"host system". Because Fieldbus integrates all parts so well, the "system"is no longer an island separate from the "field devices". I.e. the "system"is the whole thing including both host, networking and field devices.Jonas- - - - Ian,I believe that each segment should be identified by a group of x characters.Something like:AAUUNN, where AA can be area, UU unit and N sequentialnumber. Each ancillary device would receive the AAUUNN-T1 for terminator 1,AAUUNN-JBxx for the junction boxes, etc.The LAS indication is OK in the wiring diagram, but I am not so sure aboutthe function blocks. They should be in the functional diagrams, where theassociation with the physical device can be made. Quiescent current animportant information.The Terminator should be clearly identified by a different color, text or abig T. I don't like terminators in the devices. Removal of the device wouldcause inadvertent removal of the terminator.Approximate cable length would be a good optional information, mainly if ISbeing used.The diagram should contain all devices in the segment, their tags, Junctionboxes or t's that they are connected to and the relative position of theterminators.Plants with pre determined instrument installation stands could haveInstallation stand location/identification.The functional diagram would contain the function blocks functionallyconnected and their instrument location.Regards,Marcos- - - - IanAttached is an example of how H1 loop will probably look for AOSproject. Need was to generate loop drawing from INtools and also havesimilar look to conventional analogue loops (we'll only have about a 30%H1 loops).Gordon <<AOSLOOP.PPT>> - - - - Ian,Attached is a loop drawing for a FF installation. I have some questions onthedrawing symbols that should be used on P&ID's. I have contacted ISA andtheytell me that they do not have any standard symbols to be used on drawingsfor FFinstallations at this time and that they are working on such. Do we use thedashed line (electric) or should we go with the Data link line symbol (linewithsmall circles) to represent the wiring between devices. How about the devicesymbol since ISA hasn't come up with one yet. Sq. Box with circle insidewithhoriz. line or hexagon. or how about a new one sq. box with hexagoninside????Maybe we use the DCS symbol and just right "FF" beside it. Everyone here hasdifferent ideas. I realize that ISA will eventually come out with one but weneed a std. symbol now. Any ideas??Rick<<Mac Word 3.0>> - - - - I agree with Chuck that it is a good idea to include the segment lengthinformation on the segment drawing but think the other information hesuggests be on either the data sheet or some other database.Ian- - - -[Verhappen, Ian] To answer this question and an earlier one aboutInTools/database FF information on a drawing:1. InTools version 5.1,due out in the next few months supports anautomatically generated simplified segment drawing.2. Most CAD packages support 'scripting' to link the drawing to an externaldatabase, thus making it possible to generate segment drawings on demandonce a template to map the fields to the appropriate area and drawing levelhave been created.- - - - -Original message - - - - - Ian,1. Keep the name segment drawing, in case of the example below thereare additional spurs, and no additional segments.2. For either mechanical or electrical maintenance knowledge of theBLAS is required. I suggest to show this functionality on the segmentdrawing. It would be beneficial of having a dynamic import/export connectionto a tool like INtools to keep the information current at all times.Richard Willems- - - - To answer Richard's questions about symbols on P&ID's, ISA is not planningto differentiate via the P&ID bubble between a Fieldbus device and anon-fieldbus device. The reasons are as follows:- do we then develop a different symbol for each type of smart device? (i.e.HART, Profibus, FF, etc.?)- Fieldbus will NOT change the function of the device on the process. Atemperature Tx will still measure temperature and a valve will still openand close to control flow/pressure.- the 'loop' (I mean segment) diagram will be used for troubleshootingfield/device problems so it is here the technician and engineer will need toknow what type of devices are installed and how they affect control.The ONLY change I think that will happen to P&ID's will be the use of thefollowing interconnecting symbol to show a fieldbus communication linkbetween devices and/or host systems.<<...>> IF you are diligent about using the above interconnecting line for all yourfieldbus devices, you will know in this way that the device is fieldbusenabled.Ian- - - I think we should keep the conventional symbols used on P&ID's, as Ian said a Tx will still be a Tx and a valva a valve, but in the other hand we must identify the function blocks in each device so the control strategy.This will be a good challenge.Rick Castaņeda- - - - Ian,Thanks for the reply. Agree with the field instrument symbol (bubble) notchanging. My question was really for the Honeywell DCS symbool vs. theDeltalVPC/Controller symbol, but the same philosphy could apply here as well.Rick- - - -Dear Ian,I'm coming in late in this discussion... anyway here are two points that mayor may not be relevant:1. FF distinguishes between PD_TAG (physical device tag) which is thetag of the device as a whole and FB_TAG (function block tag) which is thetag of just one block. I would use the PD_TAG in the Network diagram(formerly loop diagram) and the FB_TAGs in the P&ID. Just like the P&IDpreviously did not shown which CPU card a block was in I believe it will notbe shown in the P&ID which FF device the block is in.2. There are perhaps two different kinds of multivariable transmitters.One is the spruced up pressure transmitter with three sensors for DP+P+Twhich is not really used to make three measurements, but rather to calculatejust one being mass flow or normalized volumetric flow. I imagine such adevice will often be represented only by a single AI block (for flow) in theconfiguration tool and therefore a single bubble in the P&ID will do. Ibelieve that DP+P+T will exist only as three or possibly one transducerblocks, not function blocks. (I see only function blocks in P&IDs becauseresource blocks and transducer blocks are device configuration, not controlstrategy configuration).The other type of multiple variable device is more of a multiplechannel device, such as many FF temperature transmitters that make twomeasurements which generally are independent (although can be used in aredundant scheme etc.). Just like a box was not drawn around measurementsdone in the same card, I think it will not be done around measurements fromthe same FF device.Jonas- - - - - - - This sounds reasonable, however it is a bit of a problem in my circumstance.We are a reasonably small chemical company, and don't have a great manycontrol loops, being mainly batch processes. So we don't have loop diagrams.The P&ID is really it as far as information goes. I would be using FF mainlyfor the field wiring aspect for tanks etc with level, temperature and a lotof discreet valve opening devices.If I don't show all the info on the P&ID, it won't be seen (by theinstrument techs/electricians doing work) . Unfortunately I can see thisleading to a very cluttered P&ID. I might have missed a couple of earlieremails if they addressed this.Any thoughts? BTW, I am an Engineer (Mech,projects) so my instrument knowledge is onlywhat I've seen here and at my previous company. The P&ID was about all thatI ever saw. ie I might have some pretty big gaps in my knowledge.rm - - - - - - - - Ian,Like Jonas, I am coming in somewhat late on this discussion and have foundit interesting to read through everyone's opinions. After discussing thisinternally with a few people, I agree with Herman that this is "cat herding"at its finest.I see two main threads to the discussion - how to represent multivariabledevices in general and how to represent fieldbus devices (including FF),multivariable or not. Multivariable devices have several forms and include HART and fieldbustypes. These should be depicted differently, using standard electricalconnection lines for HART and something different for a fieldbus - perhaps adashed line, with the letter "B" for buss, superimposed over it. Usestandard symbols, such a circle for a field device, tag it with themultifunction [U], and denote the functions using text labels next to thesymbol to reduce drawing congestion. Anything more complex than this can beshown on a reference drawing.I agree with the majority comments about showing the control scheme and notphysical connectivity. The critical relationship is between themeasurement(s) and the final control element and, from the P&ID, it doesn'tmatter what other sets are on the same wire. That would be depicted on thesegment drawing. About the only thing that you would want to do is tocontinue to differentiate one type of signal from another. The normal dashedelectrical line should be used on fieldbus devices because they are stillhard-wired electrical connections. A superimposed symbol or letter woulddifferentiate from analog electrical. If desired, I think it is possible toshow the PID algorithm in the field device by using standard ISAconventions. In a valve you could show FCY instead of FY or FCT instead ofFT in a transmitter.I have added some alternate ideas (just rough sketches) to your Powerpointdrawing relating to HART and fieldbus.I also think that a subtle shift in thinking is necessary with fieldbus.While we may say that the P&ID shows logical and not physical connections,the physical connections of analog pneumatic and electrical devices werealways implied by their point to point nature. We have gotten used tointerpreting and troubleshooting from the P&ID based on these implications.With fieldbus it is possible to chain several devices on the same wire andthis will upset some assumptions about interactions, redundancy, etc. Justsomething to be aware of.Overall, I think we should try to maintain some kind of "workability"balance (for lack of a better word) with P&IDs. They need to be both assimple and as explanatory as possible for all who need to use it - managers,engineers, operators, technicians, inspectors, etc. Many control and logicschemes are so complex that they cannot be effectively conveyed on the P&IDwithout making it useless as a visual aid. Drawings will be easier tomaintain if functions remain separated instead of being shown multiple timeson different drawings. A somewhat contradictory point is, that the P&ID istypically a "controlled document" while loop sheets, control descriptionsand other instrumentation drawings are not. Therefore, the P&ID needs tohave as much information as possible to prevent day to day working drawingsbecoming "controlled documents". It's a matter of striking the rightbalance.Thanks,Gary AddisonEquistar Chemicals LPControl Systems EngineeringChannelview, South Admin III # 347281.862.5347<<Sec_4_9.ppt>> - - - - Just to let everyone know, that ISA 5.1 is leaning towards the following forrepresentation of digital communications on P&ID's- fieldbus signals will be a dashed line with filled in circles.- other serial communications (i.e. Modbus) will be a dashed line with opencircles (same symbol as today)IanP.S. This comment also applies to Jim Spragues FF standard document.