1769 vs. Point I/O on CompactLogix

I have a project coming up that will be using a CompactLogix to replace a SLC including the I/O. That brings me to my question. Which of the above should I use? What are the advantages/disadvantages for using each? I have always used 1769 I/O with CompactLogix so I'm famililar with it. Not so with Point I/O. Here are some of the details:

1. All the I/O is local to the panel containing the processor.
2. We'll need the equivilant of (2) 1746-IA16, (2) 1746-OA, (1) 1746-IB8, (1) 1746-NO4I and (1) 1746-NIO4V.
3. The current SLC I/O goes to an existing vertical terminal strip.

Some Point I/O questions:

The I/O will be on Ethernet of course, but I'm confused as how the Point I/O is configured. I have read the manuals, just maybe not the right ones.

1. I understand that the Point I/O Ethernet adapter supplies the power. What or how is the power supllied to the aptapter?

2. How do I calculate the power supply needed?

3. Do I need to order the terminal bases separately?

4. When do you use the power extender?

5. Does the IAB software help with the config?

I'm sure I'll have more questions, but this is a start.

Thanks!

I have a project coming up that will be using a CompactLogix to replace a SLC including the I/O. That brings me to my question. Which of the above should I use?

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1769 I/O if its local

I agree that this I/O mix is definitely best suited to 1769 Compact I/O.

That being said, some answers on POINT:

1. The 1734-AENT adapter has a terminal block that receives 24V DC and connects it to the power bus of the POINT system. You can add power extenders or power isolators to get many modules or switch to AC power on the power bus.

2. I calculate the power requirements by hand, but IAB does a very good job of summarizing them for you too.

3. There are 8-pin and 12-pin terminal bases, and each type has a Screw or Spring option. Therefore they're purchased separately from the I/O modules themselves.

Each terminal base includes the base plus a removable terminal block (RTB). They're usually sold in boxes of ten. There are one-piece nonremovable TB versions too. The RTBs can be bought individually as spares/replacements.

4. Use the power extender when you run out of 5V (the data bus) or 24V (the power bus) power, or when you want to use AC, or divide analog from discrete. My recollection is that you can get a maximum of 17 POINT modules without adding a power extender, but it's probably fewer with high-draw devices like serial or SSI or analog.

VERY VERY VERY IMPORTANT: All the POINT network adapters connect their 24V DC supply to the POINT power bus. If you connect AC modules and AC power without a power distribution module, you will smoke the network adapter and all the other DC and analog modules. It's been done.


The 1734 POINT Selection Guide is really nice, and IAB does a good job too.

If you're going to Automation Fair make sure you see the newest low-end CompactLogix controllers: they use 1734 POINT as their I/O bus instead of 1769 Compact.

Thanks guys. I thought the same thing for this situation. Point I/O I guess is better suited for distributed I/O located away from the processor. I was only considering it from a cost perpective. I'm updating my IAB just to learn about Point I/O. When I need to use it, I can't spend the time to learn it.

So when you mixe AC and DC modules, you need a power distribution module?

As an afterthought, does the Point I/O give you more features than 1769?

In short: when you use both AC and DC, you separate them with a 1734-FPD Field Potential Distributor module. Think of it like the barrier between groups of terminal blocks.

The 1734-EP24DC and 1734-EPAC are "extension power supplies" for when you have a large number of POINT modules. They also serve to separate the power bus.

The main selection criteria for me between the two platforms is granularity; if I need three Inputs and two Analog channels and one Serial channel, I can do it with POINT much more easily than with Compact.

The availability of POINT with ControlNet and Ethernet adapters makes POINT also usable with ControlLogix.

Ken can you point use to any data on that new controller? I have a few new applications.

Jeff, all I have is some screenshots from a marketing presentation. I don't want to speak out of turn and describe products that aren't launched or might be delayed or changed.

There will be several new models of CompactLogix, all with DLR device-level-ring Ethernet and with varying amounts of memory and varying numbers of remote EtherNet/IP devices and CIP Motion axes.

I'm not going to be able to go to Chicago for Automation Fair 2011 so I'll have to wait for the spring On Tour events or for my salesman to come by.

I understand not saying to much.

My offer still stands if you ever out this way I will buy the first couple of rounds.

I'm a big fan of the point IO. I often use it even in the panel with the main PLC instead of rack mounted IO just to avoid going to terminal strips and to keep the panel space down. They are cheaper and easier to maintain as well.

My only complaints are the network modules do not seem to be robust. I have seen quite a few with failures.

I also have had issues with the digital outputs (OB8, OB8E, etc.) They are wimpy. Even switching the coils of small ice cube relays with suppression can cause the IO module to fault.

That's why I was thinking of using Point I/O. It creates its own terminal strip. I updated my IAB and correctly inserts the power distribution module for AC cards. It seems like it would be best to insert the DC cards first, next to the adapter then an distribution module then the AC cards.

Some one sent me a PP of the new RA products that you are talking about. I don't know if I can post it. It says for internal use only.

When I mix DC and AC, that's the way I do it; Adapter, DC cards, EP24AC (there's one on my desk now) then AC cards.

And yes, keep any presentations on unreleased products internal.

DamianInRochester said:

I'm a big fan of the point IO. I often use it even in the panel with the main PLC instead of rack mounted IO just to avoid going to terminal strips and to keep the panel space down. They are cheaper and easier to maintain as well.

My only complaints are the network modules do not seem to be robust. I have seen quite a few with failures.

I also have had issues with the digital outputs (OB8, OB8E, etc.) They are wimpy. Even switching the coils of small ice cube relays with suppression can cause the IO module to fault.

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You can use IFM modules with Compactlogix and they are quite robust I really like the individually fused model for outputs, this can also replace your terminal strip. But i think they do take up more space than point I/O.

kwires said:

You can use IFM modules with Compactlogix and they are quite robust I really like the individually fused model for outputs, this can also replace your terminal strip. But i think they do take up more space than point I/O.

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Yes, they work fine. But you don't save any space on your rack since it is just a breakout.

Also, if you price out getting rack IO, and IFM modules and cables versus the Point IO I think the point IO method is much less expensive as well.

Yes Sir
I am sure you are correct, i was just thinking in terms of robustness (not sure thats a word) and replacing the old terminal strip. And there probably is a substantial cost difference. I just really like the compactlogix platform personally.

kwires said:

Yes Sir
I am sure you are correct, i was just thinking in terms of robustness (not sure thats a word) and replacing the old terminal strip. And there probably is a substantial cost difference. I just really like the compactlogix platform personally.

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You are right, the robustness is still an issue with what I said. I like the Compact Logix platform as well. It is rare that I need to move up to a Control Logix, and even then it is usually due to the customer overspeciying to jive with what they keep on the shelf.