Micrologix IO, missing IO cards

[thingstodo]

I am trying to 'standardize' several HVAC units running micrologix 1400.

My question: Can I 'leave out' IO cards in the IO map below or do I need to have the IO cards that I do have in order without blank spaces for example 1.0 - 1.3?

If no one can answer, I can assemble the cards and try it myself in a couple of weeks

The general idea is to have:
- analog input card channels 1.0 - 1.3 used for things that are optional
- analog input card channels 2.0 - 3.3 used for the minimum system inputs
- RTD input card channels 4.0 - 4.3 optional, data that is supplied by another system via communications inside the mill but measured in stand-alone units without full-time communications
- analog output 5.0 - 6.1 used for the base system
- analog output 6.2, 6.3 optional for exhaust dampers, heating bypass damper

Existing units with micrologix PLCs sort of follow this grouping and have a bit of flexibility and can be arranged to work this way. Other PLCs (schneider) are now wired in the approximate order above. If I can use the order above, I can use the existing wiring reach the IO cards for most of the units. Obviously some inputs are optional and were not implemented in various HVAC units.

It would be great to delete the code for the optional inputs when they are not implemented .. and keeping the control code as close to identical as I can.

It would also be great to 'leave out' the optional analog input and RTD input cards if required during commissioning since the delivery on these cards is ABYSMAL.

If I can't leave a 'space' for a card, I will need to add some terminals and extend some of the wiring. It's still possible, but not as clean.

 

[Ken Roach]

MicroLogix I/O mapping has to match the actual modules installed in the expansion backplane (1762 or 1769).

I recently got a system in for retrofit that had a 1769-IF8 analog module installed, with nothing connected to it but a DC Common. I found out it was because they didn't want to change the program addressing for the two modules to the right.

You can certainly build an I/O mapping or abstraction routine, then configure it for the correct Slot numbers for each variation of your system.

But there's no such thing as a 1762 "Address Reserve Module" and the rackless / daisy-chained ribbon cable expansion connection means that the physical order of the modules determines their Slot number in I/O memory.

 

[thingstodo]

No such thing as 'Address Reserve Module'

MicroLogix I/O mapping has to match the actual modules installed in the expansion backplane (1762 or 1769).

I recently got a system in for retrofit that had a 1769-IF8 analog module installed, with nothing connected to it but a DC Common. I found out it was because they didn't want to change the program addressing for the two modules to the right.

That sounds messy, but I can identify with that!

You can certainly build an I/O mapping or abstraction routine, then configure it for the correct Slot numbers for each variation of your system.

I guess my base configuration will be IF4 IF4 OF4 OF4 IF4 IR4, moving the optional inputs to the right ... and I need to find some room for terminals to extend the wiring

I do have IO mapping in the micrologix. That's the only way I found to do simple simulation.

But there's no such thing as a 1762 "Address Reserve Module" and the rackless / daisy-chained ribbon cable expansion connection means that the physical order of the modules determines their Slot number in I/O memory.

Thanks for the confirmation Ken.

I could not find anything about an 'Address Reserve Module' .. but I was hoping.

I'm sure this answer will be referenced by many people over the next few years!

 

[swimmy67]

On the ML1400, Double Click "IO Configuration", Double Click the IO Module in the setup tree and check the box "Ignore Configuration Error"

 

[thingstodo]

On the ML1400, Double Click "IO Configuration", Double Click the IO Module in the setup tree and check the box "Ignore Configuration Error"

That is how the IO is set up right now. All of the IO cards have the "Ignore Configuration Error" check box checked.

Does this mean that a missing IO card that was never there, say in slot 1, is ignored but the next card in line shows up properly as slot 2?

That would be AWESOME!