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Maximum expansion IO modules per adapter

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I seem to have bumped to an undocumented limitations on I/O expansion module count per adapter (EX-A1 or EX-RC1).

The hardware configurator allows us to place 8 ATC8 modules on the rail without error. (Also, note that with 8 ATC8, the 5Vdc power limit is not exceeded). However, we get an error message when we try to configure the entire 64 channels available.

post-99-085470300 1307314615_thumb.jpg.

The error start to appear on the 50th channel. Actually, when mixing a combination of digital and analog I/O modules, the limit appears to be 50 words.

If 50 IO words is actually the limit, then it should appear on the documentations as it is an important information for sizing the PLC.

We need the entire 64 AI channels per rail. Is there any work around aside from adding another adapter module?


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Two notes:

1. "Limitation" CANNOT be metioned in any documentation, as it depends on many factors. This number comes from limitation in communication between PLC and EX-A2X. As Yair stated in his post above, in bottom line of Hardware configuraiton window (VisiLogic) there is a "calculator" of communication load. Any one can check before starting to build his project.

2. In fact, there is no such limitation! You can add Remote adapters EX-RC1. To each adaprer you can connect, let's say 6 x IO-ATC8 = 48 universal 14 bit AI. You can connect up to 60 x EX-RC1 to one PLC. This means - 60 x 48 (via RC1) + 48 (on A2X). In my calculator the number is 2928. You can add another few analog I/O on board or Snap In module, but this will not change the final situaiton drastically.

BTW - having 6 x ATC8/AI8 ot each adapter, you can still add up to 2 more I/O modules with digital I/O...

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As I understand the issue, there is a 50 words limitation for local I/O expansión. 16 points digital input or output uses 1 word, so, one can mix any cards as long as they do not exceed such limit.

Am I correct?


I tried 6xATC8/AI8 + 1xIO-DI16 + 1xIO-TO16 and calculator shows 100% capacity, but also got same error of original post

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