I use Mech Desktop and Inventor..... and have little experience or understanding of electrical schematics.
However..... my boss is trying to create electrical "loop" sheets for PLC automation using plain jane Autocad.
It seems very cumbersome doing this. Basically like using Autocad as an Etch a Sketch.
Would "electrical" be a much better "tool" for what we are trying to do?
And..... some general questions Id like advice on. If doing electrical schematics in plain Autocad... should one NOT use paper space for the text and border.... and instead keep everything in model space?
With some minor programming like creating blocks with attributes, AutoCAD could meet your needs. It depends on how often you will be doing these schematics. It may be worth the investment.
Personally, I like to annotate in paper space but to create sketches for minor changes, annotating on model space is easier to plot. Annotating in paper space also allows you to change the scale of model space without affecting your annotations. I think the AutoCAD world is split either way.
Sincerely,
Donald L. Phillips, Jr., P.E. Worthington Engineering, Inc.
145 Greenglade Avenue Worthington, OH 43085-2264
snipped-for-privacy@worthingtonNSengineering.com (remove NS to use the address)
I use Via Lite... The old version has its limitations but for what we did it was ok...They got bought up by autodesk (go figure) and are now marketed by them. If you do enough work to justify it they may be worth looking at if you already own Acad anyway. I would never buy acad for that purpose tho...
In my experiance there is never enough time, and doccumentation is one of those tasks that gets under estimated, short circuited and pre-empted. To use Acad basic for this seems to me to be a real problem if you plan to do it in the course of buisness... If you wanna do it now and then well thats differant...
I dont know about you guys but I hate paperwork, and making that rtask easier is ALWAYS my goal....
I agree, the devil is in the details which is in the annotation. Another thing to remember is object linking and embedding (OLE) makes some of this really easy. For instance, a panel schedule done in Excel and that spreadsheet literally embedded in AutoCAD. To create the same look and feel in CAD would take hours. I sometimes use Office products outside of CAD and embed them. AutoCAD 2002 made this also idiot-proof.
Sincerely,
Donald L. Phillips, Jr., P.E. Worthington Engineering, Inc.
145 Greenglade Avenue Worthington, OH 43085-2264
snipped-for-privacy@worthingtonNSengineering.com (remove NS to use the address)
A Loop Sheet, in the context I believe your are using it in, is associated with individual, or multiple, control circuits. It can be represented in a few different ways. It could a diagram of one individual loop, or the loops of a complete system, or a number of interrelated systems. They could also be presented in a few different formats. There is usually additional data on the loop sheet relating to the loops, or circuits represented. That could include, but not limited to, specs. on loop instruments, splice or termination points, set points (temp, flow, and pressure, settings), location of instruments, and other data pertinent to the loop, or system. The loop sheet is necessary for tuning, trouble shooting, maintenance, and changes to the process being controlled.
An example of a simple loop sheet for a system could be a tank with product being drawn out for a manufacturing process. The factors needing control might be the amount being drawn out and at what rates, the amount being replaced and the rate needed to keep the tank at a constant level with the tank influent being a mixture of multiple liquids each needing to be added at a specific ratio while being supplied at different and changing pressures, the possible need to keep the tank contents at a specific temperature, and all these variables needing to be kept within a tight tolerance to meet some standard, or risk substandard production of the end product.
A loop sheet could be equated to a schematic, or print of an electrical system, and would be just as useful, or useless, depending on if its been kept up to date or not, and the ability to locate it at a moments notice (it's 3 AM - all the managers and engineering staff are away from the plant, liquid is spilling from the overflow of multiple tanks, the maintenance staff can't access the loop sheets because the manager keeps them locked in his desk in his locked office, and the process could become extremely unstable, might be hazardous, be worth thousands per gallon, or take weeks to restart production if it isn't shut down properly).
Working on a complex, or even some simple, control systems without loop sheets would be like a doctor having orders to do an amputation, and not being given the information as to which appendage needs to be removed, and being told, "oh, he's in there", accompanied with an arm gesture towards the hospital. :-] Hey don't laugh, it happens!
Louis--
********************************************* Remove the two fish in address to respond
Ladder logic schematics tend to represent an off - on, or digital world. For example a home heating thermostat is measuring an analog quantity, and its output is digital off - on. There is a limited artificial intelligence capacity with ladder logic components (with minor exceptions). Ladder logic schematics are more discrete in nature showing subcomponents of a device such as a relay contact.
Loop Sheets represent devices in an analog word, components are represented as assemblies (individual internal components of the part aren't usually shown), and most often consist of analog output sensors, analog controllers with varying levels of intelligence and complexity, and analog input control devices. Loop sheets are drawn, and represent components more in a block format like a logic flow sheet.
Comparing the two is like the correlation between an a kid's wagon, and computerized package sorting conveyor system you might find at a UPS Distribution Center. They are both capable of transporting packages, but there are rather unique differences.
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