PLC 5 as RIO to CLogix

Hey guys,
First post here, we are attempting to upgrade a PLC5/40 to CLogix. Converted the program by hand, used addressing scheme that we have used several times before where we don't have to change wire numbers, simply alias everything so techs don't get anymore confused than they already are!!
Problem with this one is that the PLC5 has 16 point cards, everything else we've done had 8 point cards!! This was much simpler because all of the "groups" would line up with the I/O that was automatically created in the CLogix processor.
The PLC5 has a 12 slot rack, and is using 1 Slot addressing. PLC is in slot 0 and will be changed to an RIO card. Slots 1-4 have 16 point input cards, and slots 5 - 8 have 16 point output cards. So, the confusion comes when we are trying to figure out how to point to PLC5 address O:010/00 - O:010/17 in CLogix. We run out of addresses, even when we tell CLogix that there is a Full Rack connected to the RIO card!!
Do we just need to add another rack to the CLogix configuration, or do we need to actually install another PLC5 rack and then add that to the configuration???
Thanks in advance for any assistance!! I can post the offending programs if that'd help...

Welcome to the forum Harley.

I was at the SLC AB office the other day and noticed something that didn't quite look normal about a particular CLX. When I inquired I was shown one of the neatest things to come from AB. AB now has an IO conversion base for super easy conversions from a PLC/5 to CLX. It lets you ditch the 1771 IO and use 1756 IO, but without rewiring any of the IO. You remove the wiring arms from your PLC/5 and pull them aside. Remove the PLC/5 rack and mount the IO conversion base in its place, then plug all the wiring arms back into it. A CLX rack then clips in place on top, and then you plug cables from the IO conversion base into the CLX IO modules. If your program is all done you can do a change over from a PLC/5 to CLX in less than 30 minutes. If you haven't committed to the RIO card yet then you might want to seriously consider this option.

http://literature.rockwellautomation.com/idc/groups/literature/documents/pp/migrat-pp003_-en-e.pdf

If you have Integrated Architecture Builder software you can enter your PLC/5 configuration and it will generate a BOM for the conversion.

Here is a video on the conversion
http://mms.rockwellautomation.com/idc/groups/multi_media/documents/multimedia/1771to1756.wmv

What exactly do you mean when you "run out of addresses" ?

This might just be the simple issue of Octal (PLC-2,3,5) point numbering versus Decimal (SLC, Logix) point numbering.

The 1771 I/O platform was created for the PLC-2, which used octal and BCD extensively. The Octal (base-8, remember) numbers for the points on an I/O module are 0,1,2,3,4,5,6,7,10,11,12,13,14,15.

Not that there's no 8 or 9. Octal uses only the digits 0 through 7.

When you move to a modern control system that uses decimal numbering, of course your first eight digits line up. But it takes discipline to remember that the old wire numbers are Octal, and the new bit numbers are Decimal.

If I had a nickel for every time I mixed up 10(octal) and 10(decimal) in a PLC to Logix conversion..... I'd have a big pocketful of change.

The discipline I enforce to try to cement this difference in my mind is that I speak the octal numbers one digit at a time: I say "One Two" when I'm talking about 12 (octal) and "Twelve" when I'm talking about 12 (decimal).

Sixteen point cards shouldn't matter. First off the PLC processor card (or scanner) does not reside in slot 0. The PLC location is not counted in the addressing. The first physical IO slot is in group 0. PLC/5 addressing uses specific terminology. You have a twelve slot CHASSIS. A rack is a logical division of the chassis and a rack consists of 8 groups (0-7) in a chassis. Depending on addressing mode, a group may consist of one physical slot, two physical slots, or one half of a physical slot. Since you are using single slot addressing then the chassis contains two logical racks. The first rack contains groups 0-7 and the second rack contains groups 10-13.

You might want to review a few forum threads on the topic.

http://www.plctalk.net/qanda/showthread.php?t=21174

http://www.plctalk.net/qanda/showthread.php?t=55940

http://www.plctalk.net/qanda/showthread.php?t=55940

I think TConnolly has a better handle on the issue; I'm probably assuming too much.

ControlLogix only understands and represents logical RIO addressing, so 'Racks' will always appear as Logical Racks. It doesn't matter if they are physically located in the same chassis or different chassis or emulated by a PanelView; they still show up as 8-slot Logical Racks.

TConnolly did indeed hit the nail on the head. I am used to SLC's and therefore did not make the distinction between "Chassis" & "Rack". So, that means that my PLC5 has actually 1 1/2 "Racks" yes? 0-7 being the first, and 8-11 being the 1st 1/2 of the 2nd. Now, that brings up the question of how to get CLogix to understand that...do I just add an additional "Rack" under the same RIO connection like I would if there were a physicall chassis/rack connected with it's own RIO card and blue hose?

TConnolly said:

Welcome to the forum Harley.

I was at the SLC AB office the other day and noticed something that didn't quite look normal about a particular CLX. When I inquired I was shown one of the neatest things to come from AB. AB now has an IO conversion base for super easy conversions from a PLC/5 to CLX. It lets you ditch the 1771 IO and use 1756 IO, but without rewiring any of the IO. You remove the wiring arms from your PLC/5 and pull them aside. Remove the PLC/5 rack and mount the IO conversion base in its place, then plug all the wiring arms back into it. A CLX rack then clips in place on top, and then you plug cables from the IO conversion base into the CLX IO modules. If your program is all done you can do a change over from a PLC/5 to CLX in less than 30 minutes. If you haven't committed to the RIO card yet then you might want to seriously consider this option.

http://literature.rockwellautomation.com/idc/groups/literature/documents/pp/migrat-pp003_-en-e.pdf

If you have Integrated Architecture Builder software you can enter your PLC/5 configuration and it will generate a BOM for the conversion.

Here is a video on the conversion
http://mms.rockwellautomation.com/idc/groups/multi_media/documents/multimedia/1771to1756.wmv

Click to expand...

I investigated this on my current project, and while the labor saving aspect of this system is great, the hardware costs alone are ridculously expensive!! Plus, I think it looks more like a "hack" job and you still have constraints. The rack becomes deeper so you need the depth to be available in the cabinet, and while the new PLC chasis is installed above the conversion base your chasis could overhang either side and you must be aware of other components this could interfere with.

I ended up using PointIO to replicate the PLC5 rack. I was able to retain the exact number and type of IO points with Point IO as well as fit it into the existing PLC5 rack foot print. All at 1/3 the hardware cost of the above converstion, and the labor was simply to remove the old rack, install the PointIO rack and re-wire. I provided a cross reference of old IO wire lables to new IO lables and it worked really well.

To the OP, I agree with the others, you need to be aware of Octal addressing VS Decimal and

Thanks Paully,
But the problem is not Octal vs Decimal, it's how to configure the CLogix to "see" the additional 1/2 rack that exists in the chassis because of the single slot addressing.

HarleyHetz said:

Thanks Paully,
But the problem is not Octal vs Decimal, it's how to configure the CLogix to "see" the additional 1/2 rack that exists in the chassis because of the single slot addressing.

Click to expand...

Harley:

Do you have access to the Rockwell Automation Knowledgebase? This is described in Article 62035. Basically, the Logix will only support 8 Cards per Logical Rack, so you need to define a second Logical Rack for the remaining Cards.

If you don't have access, I can see if can paraphrase it for you.

Stu....

sthompson said:

Harley:

Basically, the Logix will only support 8 Cards per Logical Rack, so you need to define a second Logical Rack for the remaining Cards.

Click to expand...

I've done many PLC5 to ControlLogix conversions. It's not a question of what ControlLogix supports, more an understanding that ControlLogix must have the I/O that exists configured correctly in the I/O tree.

So forget about what physical chassis you have, it's all about logical racks. Enter the logical rack addresses into the I/O tree and it all works.....

Thanks guys,
That's exactly what I was looking for. I even looked for it in the knowledge base...guess I just gave up too quick!!!