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
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?
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
I dont know about you guys but I hate paperwork, and making that rtask
easier is ALWAYS my goal....
my 2 cents worth
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
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!
Remove the two fish in address to respond
For the most part they are different worlds.
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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