RIO on AB1771 rack

Right here's the situation we have an old PLC2 which we (the techs) want rid of how ever the Boss is not keen on giving us the cash to rip it out and start again.
So plan B we remove the processor from the PLC 2 and fit in its place a remote I/O adapter module AB 1771ASB then take a spare 4 slot SLC rack with a 5/03 in it and fit a remote I/O scanner AB1747SN and away we go(we'll convert the PLC 2 prog to SLC no problems).Now can any one give me some advice on what to watch out for if we do this ?


Thanks Jezz

Go for it!

Jezz, you are about to have the time of your life if you have never done RIO before. The AB knowledge base at http://domino.automation.rockwell.com/applications/kb/RAKB.nsf/$$Search/?OpenForm is a great source for info, especially if you get in trouble. However, the SLC and associated RSLogix software make the RIO link set up a snap. Just be sure you look over the RIO cable requirements and terminate it correctly and you should have no problems. Just remember that the 1771 I/O rack will show up as just I/O in the SLC data table and it is up to you to know which ones are for what. It is really easy since the 1771 rack will be labeled based on where your RIO Scanner module is in the SLC rack. It is a great plan, go for it.

Is dropping a plc5 proc. into the rack a possibility? That has been done on a couple of our older machines. Fortunatly the machines have a newer twin that had 5's in them so we didn't have to rewrite the program.

Drewcrew6

Watch out??

I remembered this thread:
http://www.plctalk.net/qanda/showthread.php?s=&threadid=965
but that gotcha only involves PLC-5's, not ASB, and PLC-2 racks. You might want to doublecheck the principle, though, namely that certain chassis may not be compatible with the ASB.

I also remember another thread about how certain PLC-2 racks don't support more than 8-bit I/O modules. This shouldn't be a major hurdle, but it could cause confusion on your expected addressing.

Otherwise, I agree with drew, have a ball.

1771 I/O racks are just that, racks. It is the plc that determines wheather you can do certain things regarding I/O addressing etc.

Knowbase document A16647 is indespensable when converting PLC-2 hardware to modern A-B controllers.

http://domino.automation.rockwell.c...9AD7A2D5130BEEA485256AFB0064833C?OpenDocument

You ought to be able to put a 1771-ASB into this chassis without any trouble.

Post a list of the I/O modules and maybe people on the Forum who are familiar with the 1747-SN can give you an example of how the former PLC-2 data table will be represented in the SLC-500 data table.

The I/O that's already in the rack is as follows

6 * 32 point DC input cards 1771-IBN
5 * 32 point DC output cards 1771-OBN
3 * 16 point 110v ac output cards 1771-OAD

We have all ready looked at getting a PLC 5 and just slotting that in but then on top of the cost of the processor we would need software we have RS Logix 500 on site all ready and are all familiar with it

Jezz,

I did the same thing with 2 racks of old 1771 i/o. The only thing is I had no 32 bit cards--this means 1/2 slot addressing--which the chassis is set up for already. But I don't know how the 1747 scanner handles it, for sure.

6 * 32 point DC input cards 1771-IBN
5 * 32 point DC output cards 1771-OBN
3 * 16 point 110v ac output cards 1771-OAD

That's 14 slots but 25 groups or words. The 1747-sn alloows 32 so I think your OK.

I had 2 16 slot racks so each one was actually configured as 2 logical racks--single slot addressing--your one 16 slot rack will be configured as 4 logical racks---1/2 slot addressing.

The tricky thing here is that you'll have 32 words of data all referenced to the slot of the SLC where the SN module is--I:1.0/0 thru I:1.31/15. In your case if there's a 32 bit card in your first slot, it will be words 0 and 1 in the SN slot. Point is, it's not as easy to look at the SLC address on a printout and readily find the physical I/O ppoint in the rack--because you lose the slot/bit info to the word/bit stuff.

Another thing--I:1.0/08 in the SLC equates to I:0/10 at the physical input point. the 1771 cards are octal--the SLC I/O table is decimal.

If you would assign symbols to the SLC bits that relate to the physical I/O and it would be helpful. ie I_0_10.

Good luck,
have fun

I did exactly this conversion once on a Banbury Rubber Mixer in a Tyre plant. All the above is true, however I do recall one oddity that caught me unawares.

It turned out that the SLC scanned a lot faster than the PLC2 and in the program I converted this caused a very obscure bug. I can't recall the exact details of the bug, but in general you may just want to keep this thought tucked away in the back of your mind as a possible source of problems.

Overall the conversion is a bit of a b**** and I wouldn't volunteer to do it again. Nothing converts smoothly from octal to decimal and either you finish up by converting most of the code literally into less than elegant SLC program, or you finish up re-writing the whole damm thing from scratch.

Two questons :-

1. Hows my I/O going to apear
slots 1 to 6 are 32 point Inputs
Slot 7 is 32 point output
Slot 8 is empty
Slot 9 to 12 are 32 point outputs
slots 13 to 15 are 16 point outputs

2. Whats 1/2 slot 1 slot and 2 slot

Thanks Jezz