Nate Holt's Blog

May 13, 2010

Tutorial- Customizing ‘Type 4′ contact pin list assignments – AutoCAD Electrical

Filed under: Electrical, Tutorials — nateholt @ 6:19 pm

Smart “type 4” contact pin assignment extends capabilities beyond just “normally open / normally closed” contact states.

Note: Autodesk’s Nathan Eliason hosted a webcast last month that focused on AutoCAD Electrical’s contact and pin assignment tracking features. I helped put the demo together and was responsible for the real-time Q & A support while Nathan was “on stage”.  

This posting is a brief summary of what Nathan demonstrated at the very end of the webcast. It might serve as a simple tutorial of setting up an enhanced version of the “pin list” feature in AutoCAD Electrical. 

Related tutorials: Tutorial – AutoCAD Electrical and Contact Pin Assignments, Off-beat Uses of Toggle NO/NC Command, Tutorial – Setting Up New Device “Pin List”


In the previous tutorial we looked at a hypothetical parent safety-relay component that had two different types of “normally open” contacts – it had some N.O. contacts meant to switch “power” and another type meant only for auxiliary control use. Both types were marked “normally open” but mixing them up was not really an option. We wouldn’t want to accidentally assign an aux N.O. contact for use as a N.O. power contact. It might work one time, but that’s probably about it.

To help work around this issue, the previous tutorial showed how we could add “comments” to the encoded “pin list” string for the parent component. These comments then show up in the “Pins in Use” dialog and help guide us in making an informed contact assignment.

Here are a few screen-shots extracted from that tutorial…

Here’s how the dialog might look without the comments. The first three N.O. references are “power” contacts and the “13/14” one is an auxiliary N.O. control contact. All four are N.O. contacts tied to the parent device “SC429”, but it’s not apparent from the list of available N.O. contacts which are “power” and which are “control”. You could guess, but it would be just that… a guess.

And here is how the previous tutorial explained how to add in flagged “comments” into the pin list string. Here the first three pairs of pins are marked with a “PWR” comment…

… so that the dialog gives a bit clearer explanation to the user to make an informed choice:

A Second Way – Using the “Type 4 – Other” contact type

This method is a bit more complex but yields an automatic assignment of the correct pair of pin numbers for a power versus aux control N.O. contact insertion. It was touched on in a posting a couple years ago here, but is dusted off and re-presented below.

It is based upon two things: 1)  adjusting the “power” N.O. contact references in the encoded pin list string to use “type 4 – other” instead of “type 1 N.O.”  and 2) creating a separate N.O. contact symbol to be used for “power only”.

For encoding our “power” N.O. contacts into the pin list, we decide to create a new “type 4” pin list type called “4P1”. Our code must start with the digit “4”. After that, it’s totally up to us.

So, we go back into the Pin List Database Editor tool and edit the ACME record we added in the previous tutorial. We change the “type” of the three N.O. power contacts from “1” to our special “4P1”. Hit the Save/Exit button.

Now, our final step is to create a new N.O. contact library symbol to be used only for “power”.

We’ll just make a copy of the existing N.O. motor starter / contactor library symbol “HMS21.dwg”. We’ll name the new version HMS21_4P1.dwg.  Add a non-visible attribute definition PINLIST_TYPE and give it a default value of “4P1”.

Just for clarity we’ll flip the two vertical lines to Polylines and give them a wider “width” value so it will be easy to tell the difference between a “power” N.O. contact and a normal N.O. contact.

Testing !

Okay, let’s test our new full-automatic assignment mode and see if it works. Insert the motor starter / contactor coil as outlined in the previous tutorial. Make ACME catalog assignment as before.

 BUT, before exiting the dialog, it is beneficial to make one small adjustment. Hit the “NO/NC Setup” button…

Make this quick adjustment. Bump the “Maximum NO contact count” back up to a total of 4.


The reason it now comes in as a value of 1 instead of the previous value of 4 is that we changed three of the N.O. contacts from type “1” N.O. to special type “4P1”. AutoCAD Electrical does not know that these are still considered to be N.O. contacts… so we make this small adjustment.

If we skip this step, AutoCAD Electrical may pop up an unnecessary alert dialog when we try to insert a second N.O. contact, whether it is a power contact or a normal auxiliary contact.

Hit OK after bumping the count up to 4 N.O. for this parent coil. Hit OK to exit totally out of the Insert/Edit dialog.

Okay, now cross your fingers. Now we’re fully ready to test.

Insert a generic N.O. auxiliary contact and tie it to the Safety Contactor parent coil.

AutoCAD Electrical finds the first (i.e. “only”) N.O. contact in the coil’s catalog pin list and defaults to pin pair 13 and 14.

If we hit the “List” button on the dialog, we can see that AutoCAD Electrical is displaying only the one set of N.O. pins as an appropriate pick.


This is good.

Now let’s try an instance of our special “power” version of a N.O. contact. We insert an instance of our modified “Power” N.O. symbol and tie it to the Safety Contactor parent coil.

AutoCAD Electrical notices that this symbol has a non-visible attribute PINLIST_TYPE on it, and this attribute carries a value of “4P1”. AutoCAD Electrical checks the parent coils pin list data and finds there are three available child contact pin pairs marked with this same “4P1” code. It takes the first instance and defaults to pins 1 and 2 for this power contact.

If we hit the “List” button on the dialog, we can see that AutoCAD Electrical is displaying only these three special contact pin pairs.


There it is. We’ve customized the behavior of this feature just a bit when dealing with our safety contactor symbols.

Pretty cool.

Webcast posting for rerun viewing…

This webcast should be available at this link, or go to the main site here:



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