ControlLogix IO

Hi everyone,

Just wanted to get some thoughts on the best solution for ControlLogix IO. I've just done a comparison of 1794 vs 1734 vs 1756 IO pricing and they're reasonably comparable. In summary:

For Ethernet communications:
- Point IO has the cheapest adapters, followed by Flex then 1756

For Digital inputs:
- 1756 is the cheapest followed by Point then Flex

For Digital outputs:
- Point IO is the cheapest followed by Fex then 1756

For Analog inputs:
- 1756 is the cheapest (by a good margin) followed by Flex then Point

For Analog outputs:
- Point is the cheapest followed by Flex then 1756

Looking at a remote IO 'rack', well it's difficult to see who comes out on top in price but I believe it would be Point given the low cost of communications adapters and terminal bases, and no cost for the rack or power supply.

Prices are list prices off Integrated Architecture Builder.

Looking at the cost of installation, it all comes down to ease of termination. I believe Flex comes out on top here with the bulky bases, 1756 would be next if you use the premade cable looms and terminal blocks (adds to cost but saves on terminations), Point is last with small RTBs.

I think that it would end up boiling down to personal preference at this point, as well as what prices you can get sellers down to.

Has anyone got any opinions? I'm looking at just basic IO here; no RTD modules/etc, no isolated channels, no diagnostic feedback, just a cheap and basic remote IO rack.

I'm just trying to work out for a new medium sized process plant with ControlLogix (so a significant number of IO with no special requirements), should I use 1756, 1734, or 1794 IO with my 1756-L7X CPU.

Thanks!

I really like the Point IO (especially if you have safety IO), termination is actually easier than you think and panel space is minimal.

Personally I don't see a need for the 1756 IO platform to serve as a "remote" rack. Exception would be for high-speed counter cards, I would probably stick to 1756-HSC cards as I've had issues in the past with Flex cards (years ago probably fixed by now). Using a large ControlLogix rack then using additional termination points (either manufactured or direct wire to terminal blocks) just seems to be a large amount of wasted space in a control panel.

From a control panel design perspective I feel FlexIO is great for large installations. Typically a 30" x 60" panel will house two rows of FlexIO (totalling 16 possible modules) and all power distributions, fusing, terminations...etc with a little room to spare. Makes for a great "remote" panel, big enough for a lot of IO, small enough to be manageable to work in and around (includes panel fabrication, shipping, installation, IO check and final commissioning as well as continued maintenance).

Most of my experience is with FlexIO, used it in SLC/RIO systems, PLC5/RIO systems, Logix/ControlNet Systems and Logix/Ethernet systems. FlexIO is by far the most versatile in my opinion and easiest to design/setup. The only downside is that is a bit dated and showing it's age but I don't see it going away anytime soon.

I've gotten into PointIO lately, and I like it however you have to be more design conscious of it. I stick to 2-4 point IO blocks to better match the terminal block size so I don't have to add additional wire terminals. You also need to be aware of backplane power consumption and those FPD blocks where required. But you have more flexibility so small-footprint remote control panels FlexIO works very well as it gives you a very diverse IO set in a small footprint.

I think PointIO is easy to wire, the terminal blocks are removable so you have better access if you need it.

Did you consider the cost of panelbuilding in your analysis? 1756 costs a good bit more to wire it out to terminals. That portion of the cost is not required for flex or point i/o.

Hydro Power Guy said:

Did you consider the cost of panelbuilding in your analysis? 1756 costs a good bit more to wire it out to terminals. That portion of the cost is not required for flex or point i/o.

Click to expand...

It's something that I'm planning on building into the comparison, along with cost of power supplies, racks, removable terminal blocks, preformed cables, additional terminations, space required (will use our standard panel pricing and come up with a price per square meter).

Eventually I hope to have a spreadsheet where I can input the number of IO and it'll spit generate rack layouts, bill of materials, bill of materials, panel size required, etc. Integrate Architecture Builder does most of this but it's difficult to immediately compare a number of different platforms as well as PLCs from different vendors.

Eventually I hope to have a spreadsheet where I can input the number of IO and it'll spit generate rack layouts, bill of materials, bill of materials, panel size required, etc.

Click to expand...

Matt1234 I am also looking to build a similar Excel sheet. Just wondering if you got anywhere with this?


Thanks
--
Farhan

Paully's5.0 said:

I've gotten into PointIO lately, and I like it however you have to be more design conscious of it. I stick to 2-4 point IO blocks to better match the terminal block size so I don't have to add additional wire terminals. You also need to be aware of backplane power consumption and those FPD blocks where required. But you have more flexibility so small-footprint remote control panels FlexIO works very well as it gives you a very diverse IO set in a small footprint.

I think PointIO is easy to wire, the terminal blocks are removable so you have better access if you need it.

Click to expand...

I actually have reworked panels with Point I/O in them because, as some components age, they start draw more current and take out the input card they are attached to. Now I use 8-point cards exclusively (unless it's just not available, like a relay card), and add sensor blocks to handle all the external wiring, as well as provide a couple of 24VDC/0V rails. Depending on the I/O requirements, you can still get a nice compact installation.

JordanCClark said:

I actually have reworked panels with Point I/O in them because, as some components age, they start draw more current and take out the input card they are attached to. Now I use 8-point cards exclusively (unless it's just not available, like a relay card), and add sensor blocks to handle all the external wiring, as well as provide a couple of 24VDC/0V rails. Depending on the I/O requirements, you can still get a nice compact installation.

Click to expand...

All I can say is Wow.

yes, training is expensive - but ignorance is where the REAL money is .Ron Beaufort

The Plc Kid said:

All I can say is Wow.

Click to expand...

Must you say anything?