What scale to use when drawing System Diagrams?

Hi Guys,

Please take a look at a sample diagram I've created for my company. I'm torn on what scale or even what units I should be using, since I am not drawing real objects. When I took an entry level class, it was so much easier doing the assignments because we used a scale that made sense based on what we were drawing.

Any other general tips on how to improve my diagrams, title block, etc, would be greatly appreciated as well. Thanks!

5300_Room_Combination_reduced.pdf

Use a scale of 1:1 on schematics, diagrams, etc.

How about the units? And text size? I was given a formula to use for text size (plotted text height * scale of drawing).. so in this instance, my text height will be set to the actual plotted size?

Assuming Imperial Units being used.

Units? Set to imperial. (Not sure what you are asking with that one.)

Text size? 1/8" or .1, depends on factors like if the drawing will be reduced, company standards, etc.

Text size? yes the text height would be multiplied by the scale factor, so the scale factor is 1 multiplied by .125 = .125. So text height is actual plotted size.

Okay, thanks for your help!

Schematics are not drawn to scale.

Is everything, including the title block and border, being placed in model space, paper space or a combination of the two?

Are you using metric or imperial units?

i'm drawing in model space. when I'm done, I switch to paper space and import my title block as an xref i believe.. and the diagram is inside as a viewport (i think.. sorry im new to this haha). At this point and can position the diagram and zoom in and out.

I'm using metric/millimeter units only because i heard it's standard. I have no need for measurements with these kind of diagrams.. so if I should be using different units to make these kinds of drawings easier, I'd like to..

Schematics aren't drawn to a scale in that they don't represent distances between objects that exist in the field. But, in order to have all your schematic drawings plot the same with symbols plotting the same size you do use a scale of 1:1, with the symbols drawn to the size required (for example ISA, or internal requirements). Text size will be easy to determine if every schematic is drawn 1:1 and the viewport is scaled 1XP.

Unless you normally use metric for all your drawings I wouldn't confuse things by using metric for schematics.

Ok, this is the type of direction I am looking for, as I am the first person in my company to begin drafting and I should set some standards...

So how can I set a viewport to 1:1? As of now I just zoom in and out with the mousewheel.

Also, i don't PREFER metric.. I'd rather use empty units or pixels or something..

AutoCAD units: metric or imperial. There is no option for empty units or pixels.

If you are located in the U.S. and drawing for the home market (not international) then use a template that utilizes imperial units since in all likelihood you would be plotting to paper sizes along the lines of 8.5x11, 11x17, 18x24, 22x34 or 24 x36.

Your viewport scale can be set in any number of different ways. You might find this of some interest...

http://www.cadtutor.net/forum/showthread.php?72972-Things-you-should-know-about-Viewports.&highlight=viewports

Ok, this is the type of direction I am looking for, as I am the first person in my company to begin drafting and I should set some standards...

 

So how can I set a viewport to 1:1? As of now I just zoom in and out with the mousewheel.

 

Also, i don't PREFER metric.. I'd rather use empty units or pixels or something..

Based on r2013.

Applying a scale to a viewport, the viewport must be unlocked, see below. It is best to have the viewport layer on, unlocked, and thawed when adjusting the viewport scale. Lock the viewport after setting the scale.

A) Picking on the viewport itself, use any one of the following:

TASK BAR or (Status Bar if turned on in Options) > Viewport Scale pulldown

VIEWPORT TOOLBAR > pick the down arrow for the pulldown choices

PROPERTIES > in the Misc section change the Standard Scale (this will give you a real time view as you pick other scales)

QUICK PROPERTIES > change the Standard Scale (if this doesn't show in QP go into the CUI, Quick Properties and add it) (this will give you a real time view as you pick other scales)

B) When the viewport is current (you are working inside the viewport) use one of the following:

TASK BAR or (Status Bar if turned on in Options) > Viewport Scale pulldown

VIEWPORT TOOLBAR > pick the down arrow for the pulldown choices

ZOOM > type in a scale factor as 1/24XP, where scale factor of 24 is 1/2"=1' (there are (24) 1/2" in a foot, or 12/.5 = 24) (3/8"=1' = 12/.375=32, input would be 1/32XP at the zoom command).

******* UNLOCK A VIEWPORT ************

Viewport must be unlocked to set the scale, you can do this by any one of the following:

Picking the viewport and right clicking, picking Display Locked > No

Picking the viewport, in the lower right task bar (or status bar) use unlock icon near Viewport Scale

PROPERTIES > Cicking the viewport > Misc > Display locked > No

MVIEW command > Lock > Off > pick viewport(s)

QUICK PROPERTIES > Display locked > No

Excellent, I will take a look. We plot to 36x24 i believe, so yes that makes sense

Thank you both for all your attention and help!

So rkent, should I be working in Paper mode in the viewport, instead of model space the whole time?

So rkent, should I be working in Paper mode in the viewport, instead of model space the whole time?

Arguments can be made for either of three or more methods. I prefer to always have titleblocks in PS and the work in MS. I guess my reasoning is that all other drawings (of mine) are done that way so it keeps the work flow identical. If you get into using the Sheet Set Manager (SSM) then using PS is the way to go. If you draw multiple schematics in one MS file, you can have multiple PS sheets to plot them, keeping everything in one file. Again some argue against this and it depends on work flow. Doing it this way prevents more than one person from working on it at one time.

Some make the argument to do schematics all in PS and other than I haven't done it that way I don't have a reason for you not to. Objects in PS can't be inserted into another drawing (as in, Insert, point to that drawing) so that might be something to consider.

Doing everything in MS will work, again I work the other way for all my other drawings and like the consistency of using the same work flow. Everything in MS will keep the SSM from working for you.

Another method is to have sheets for each schematic with the work in MS. Then you create individual PS sheets for the title block and xref the MS schematics into those. For large jobs this allows the most people to work on the job and it lets designers work on the schematic while drafters work on the PS sheets for plotting.

Clear enough for you? Don't you just love choices?

... i love the support and knowledge on this site, thanks so much! Yeah, I'm going to continue to work in MS!

Up until recently all of our process piping and instrumentation diagrams (i.e. - schematics) were done entirely in model space at a 1:1 scale. For one new project we decided to use layouts as the process engineer wants the ability to effortlessly plot to several different paper sizes so this has been set up in the template itself.

You might consider creating a template with all your layers, linetypes, text styles, etc. to make your job easier.

ReMark, thanks again for the additional input. I agree with your suggestion; I am continually revising my template based on the repetitiveness of the drawings I will be doing. Luckily, beyond the components used in each system, the drawings do not change much

MVa12 - You did mention xrefing your title block and I would concur with that method. What I do is have my title block xrefed in and I only put in the text that won't change from project to project in that. Things like the company address, 'project name' 'project number', (these are the names of each cell in the title block and not the actual project name),etc.

Then I make a separate file with my attributes that is inserted into the new drawing and those are edited per project, per drawing, etc. This is where you will input the actual project name, project number, drawing number, etc.

For projects I also create a Status drawing in the project folder and xref that in as well. This may be one piece of text the starts out reading '30% REVIEW, NOT FOR CONSTRUCTION', and as the project progresses you edit that one file to '60% REVIEW, NOT FOR CONSTRUCTION', and since it is xrefed in to every drawing you don't have to remember to update every drawing.

rkent,

Is there a thread or tutorial where i can refresh on attributes? it was taught in my class that I took, but I forgot how to use it.

As for title block styling.. I am creating the company standards as far as cad drawings, and I want to make a really spiffy looking Title Block. Is there anywhere I can check out some impressive looking ones? I know they're just title blocks... but still.. i want them looking great

Hi,

I always use 1:1, with well selected paper size, normally A1, text height is 5 mm (metric) for larger texts, like titles, equipment tags, etc, 2.5 or 3.5 mm for others.

---------------------------------------

http://www.digital-drafting.com