Need help with config of 1734 IO over CNet

Hey fellas,

This is my first time working with Point IO and I've run into a snag. It's an OEM setup, so while I wait for their techs to get back to me I figured I try to find out for myself.

The project I'm working on is supposed to be "plug & play" (at least the IO side of it). The OEM shipped us an IO cabinet with everything we're supposed to need. We're building the controls, a CLX rack. I spec'd ControlNet. The CLX will have a CNB/A. The IO cabinet includes:

1734 ACNR ControlNet Adapter to which is connected, in this order:

• 10 IE8C 8ch analog output modules
• EP24VDC power supply
• 6 IE8C 8ch analog output modules
• EP24VDC power supply
• 12 OE4C 4ch analog input modules
• EP24VDC power supply
• 6 IB8 8pt discrete input modules
• 4 OB8 8pt discrete output modules
• EP24VDC power supply
• Point IO extension cable
• 22 OEM specific air valves (in groups of 4,4,2,4,4,4) in a custom Point IO chassis

I created my IO config offline but I get this error message when I try to download to the processor...


Error: MyCnetAdapter: The number of connections configured for this module has exceeded the limit.

I then removed modules one by one started at the air valve end. I have to delete 5 of the 6 air valve modules before I can download.

I try to schedule, but cannot get all of the modules happy. Lots of yellow warnings.

So after doing some digging I see there's limits to how many "connections" the ACNR can have. Analog modules use 1 connection each. I have the ACNR set up with Rack Optimization, as I understand this helps minimize connections for the discrete IO.

I assume the answer will be to add another ACNR node (or two), right? What would be the best way to divide this up? Is there a reliable limit to how many modules can be on one node, regardless of what the book says?

.TXT file attached is renamed .L5K file. Running on an L55 v16.2.

Any help y'all can provide would be very much appreciated.

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On a side note, the air valve modules will configure, but won't schedule. RSNetWorx comes back and says, “Insert address 02, slot ## failed because the device cannot be inserted into the specified slot.” I will leave that to their tech guys to resolve. I don't expect you fellas to figure that one out, but just FYI, here's the config for the blocks...

The OEM air valve stuff is from Bürkert in Germany. They gave me the connection parameters to use in generic modules. They're stuff takes up 6 slots.

• Each block of 4 uses
  • Input 139 / 4
  • Output 33 / 1
  • Configuration 120 / 6
• The block of 2 uses
  • Input 139 / 4
  • Output 32 / 1
  • Configuration 120 / 6

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There is a maximum of 25 direct connections for this adapter

You have at least 50: 28 from IE8C/OE4C and 22 from OEM valves
Generic module always uses a direct conenction

Thanks. That's what I thought. FYI, the oem valves are grouped, so only use 6 slots in the IO config.

Is the max connections of 25 a reliable limit, that is, even though it can support 25, is it best practice to limit to something less than that?

Usually customers require at least 10% spare, sometimes even more, so using all 25 conenctions is not a good idea in any case...

Once you corrected your connections (by adding one or two addapters) you may hit another limit: max amount of data per network update.

Thanks again. Much appreciated.

Just heard back from the OEM. They will be bringing in another ACNR so we can split the rack in two. I was already thinking of putting all the inputs on one and outputs on another.

If my understanding of connections is correct, that is, analog modules get 1 connection each, all discrete together get 1 (if adapter comm format is set to rack optimized), and generic modules get 1 each, that would make...

• an input "rack" with 17 connections
  • 16 analog modules = 16
  • 6 discrete modules = 1
• an output "rack" with 19 connections
  • 12 analog modules = 12
  • 4 discrete modules = 1
  • 6 generic modules (valve blocks) = 6

Does that sound reasonable?

There are 5 separate Rack connections available, they are not a part of direct connections as far as I remember.
But this will not change totals too much.