Nate Holt's Blog

August 27, 2009

Using the Multi-Connection Sequence Terminal Symbol – AutoCAD Electrical

Filed under: Electrical — nateholt @ 8:50 am

Single in-line symbol that can represent a series of up to six daisy-chained terminals

Sometimes there is just not enough room to squeeze in all of the terminal connections that a wire must pass through to get from a connection on Component A to Component B.

Here’s a field-mounted limit switch tied back to a terminal related to a PLC I/O module. It looks simple enough. But in reality, that wire passing from the “Field” to the terminal just ahead of the PLC I/O point may actually pass through a couple field junction boxes and control enclosure’s roof-mounted terminal strips.

phantomterm01

It may not be necessary or convenient to show on the controls schematic each and every one of these interm, field terminals that the wire passes through. BUT… each connection needs to show up in the various wire from/to reports. So, for AutoCAD Electrical to properly report the limit switch wiring back to the terminals ahead of the PLC module, each of these daisy-chained connections needs to be somehow defined in the schematics.

Let’s say that for wire number 503 to get from pin 14 on PRS503 to MCAB5 terminal strip TB1 terminal 45, it has to pass through these additional terminal connections:

  1. Junction box JB23, terminal strip TS1, terminal 3
  2. Marshalling panel MP1, terminal strip IN05, terminal 32
  3. Jumper out via marshalling panel MP1, terminal strip OUT02, terminal 15
  4. MCAB5 roof-top terminal strip TOP2 terminal 10
  5. MCAB5 unit 3A interface terminal strip 3A terminal 1

What if it’s just not convenient to show these five series-connected terminals on the schematic? Is there a way to add this intelligence to the wire network.

Multi-Connection “Phantom Terminals” Symbol

This is one way to do it. It is a bit tedious but does enable intelligence to be added in the form of a single multi-terminal symbol. All information for the five daisy-chained terminals (and even part numbers for the BOM) can be assigned to this one symbol (series of six daisy-chained terminals is the maximum supported).

The multi-connection sequence terminal symbol is not represented as an icon pick on the Insert Component icon menu. You’ll have to “Browse…” to it. Here are the various versions of the multi-connection sequence terminal symbol:

  • H--1_MULTI_CONN.dwg  - horizontal wire insertion, wire number changes from terminal to terminal
  • H--1_MULTI_CONN_NOCHG.dwg - horizontal wire insertion, wire number does not change
  • V--1_MULTI_CONN.dwg - vertical wire insertion, wire number changes from terminal to terminal
  • V--1_MULTI_CONN_NOCHG.dwg - vertical wire insertion, wire number does not change

Let’s select a horizontal version of the symbol that does not change the wire number through it, H–1_MULTI_CONN_NOCHG.dwg:

phantomterm02

… and pop it in at the interface point where the wire crosses the location box boundary. Doing this displays this rarely seen dialog:

phantomterm03

Now we pick on the first group of “WD_1_*” entries and hit the “Edit” button. A sub-dialog appears. We start to enter in the daisy-chained, multi-terminal connection sequence.

Here’s the first terminal’s entry:

phantomterm04

We continue through the other four terminals in the sequence, entering in the minimum connection information for each terminal in the sequence. When all five are entered, our main summary dialog looks like this:

phantomterm05

And that’s it. The five terminal sequence is all embedded into this single squiggley symbol that breaks wire 503 at the field/location box boundary. Now let’s try the AutoCAD Electrical “Wire From/To Report”.

Wire From/To Report

Here is the result of the wire from/to report that includes the single in-line multi-sequence terminal symbol in wire number “503”:

phantomterm06

This Multi-Connection Sequence Terminal support is in the recent versions of AutoCAD Electrical and probably goes back three or four releases, not sure.

Customizing the symbol

The default symbols are set up to show the list of terminal strip tag-IDs as visible attribute text. You can hide this text after-the-fact or you can modify the symbol to hide these attributes by default. Just like any other AutoCAD Electrical schematic symbol, you can call up the library symbol’s “.dwg” file in AutoCAD and change the way the symbol looks.

Results

It’s a manual data entry, but seems to give expected results. If this concept appeals to you, a set of custom application tools might be wrapped around it to fit your specific requirements. Call me.

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