RSLogix 500 Vs. RsLogix 5

mrdmrd

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Besides the hardware that each is used for what are the differences between RSLogix 500 and RSLogix 5 are they the same type of instructions sets and if I know RSLogix 500 very well how hard would it be to pick up RSLogix 5
 
Very similar. If I recall correctly the SLC/Micrologix instruction set was more or less based on the PLC5s instruction set. Most of the differences that I can think of is with the 1771 specialty modules, BTWs and BTRs (block transfers). Some modules don't actually have I/O data table space you can access directly, like the BAS module. Some other small differences but nothing that will seem dramatic.

Its been a few years since I've done any PLC3 or PLC5 programming so I might be a little off.
 
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A big difference would be if your PLC5 used the SFC capability of the (some) PLC5's that is not available in the SLC. It's pretty rare but would be a big difference.

In ladder, one instruction that the PLC5 has and the SLC lacks is the AFI.
It's easy to make do in the SLC, but I just loved the AFI.

They also differ in the terminology of the ONS and OSR one shot instructions.

These are a couple of the more commonly used differences. There are several others such as the more rare PLC5 instructions FOR - NEXT.

If you know the SLC 500 instruction set it's hard to tell the difference between the two. Most of the differences are the more rare instructions, and there is usually an easy way to do it using the instructions that are available. As far as the user interface, between RSLogix 5 and 500 they are almost exactly the same. Most of the menus, right click options, etc. are the same.
 
in addition to what’s already been posted (specifically about the Block Transfer operations) ... if you’re moving from RSLogix500 to RSLogix5, then you’re also moving to the PLC-5 platform ... one thing that you’ll need to get a handle on is the increased flexibility (complexity?) of the PLC-5’s I/O addressing ... specifically, do some research on two-slot, one-slot, and half-slot addressing ... the MicroLogix and SLCs don’t use these concepts (except in rare cases of remote I/O) and it can be quite a shock to run into this stuff for the first time while you’re “under fire” out in the field ...
 
Two observations:
1. The PLC-5 discrete I/O is in octal, can confuse some people.
On a 16 point card you have points 0-7 and 10-17.
2. The biggest difference in my opinion is that the "enhanced" 5's can do a lot more math instructions, while you could do the same things with lots of ladder, the built in instrucions make it much easier.

All that said, I think someone that was proficeient with the SLC line could hit the floor running with the 5's. As Ron mentioned the only obvious gotcha is the I/O addressing, one slot, two slot, 1/2 slot etc...
 
Greetings to all,

from Ken Moore:
As Ron mentioned the only obvious gotcha is the I/O addressing, one slot, two slot, 1/2 slot etc...

no offense taken or intended, Ken ... but just to be absolutely correct, I said that the addressing modes are ONE big gotcha ... but I also reiterated that the Block Transfers (particularly for analog signals) which had already been mentioned by other responders were another issue ...

so to nail it all down, in my opinion the biggest issues would be:

(1) the PLC-5 uses Block Transfers to handle analog signals ... and the PLC-5's analog signals will addressed to the integer files (example: N7:54) NOT to the Input Image table (example: I:7.0) like the SLC's analog signals ...

(2) the PLC-5 uses two-slot, one-slot, or half-slot addressing modes for its I/O signals ... the SLC only uses these (rarely) for certain remote I/O configurations ...

so in the "what are the differences?" department, those two are the "biggies" ... once you've got those nailed down, you can probably muddle your way through anything else that comes along ...

worse case scenario: a guy who says he "knows all about Allen-Bradley" gets himself hired as a maintenance technician for a new job ... his first work order on the first day of the new job involves a 4 to 20mA analog input signal on a PLC-5 system ... unfortunately for our hero, the Allen-Bradley platform that he "knows all about" turns out to be the SLC-500 platform ... based on his existing knowledge, he's expecting to see an analog signal with an address something like I:7.0 with a data range from 3277 to 16384 ... this is the format that he's familiar with ... this address would indicate that the input lands on the Input Image table and corresponds to an analog input module physically located in slot number 7 of the chassis ... and further, to the first channel (word number 0) from that analog module ... oops! ... the PLC-5 doesn’t work like that ... instead this rung is just one of the pieces of the puzzle ...

[attachment]

now the steps required to find and then decipher this rung ... and then to track down the “problem” signal to an address like N7:54 (and a default data range of 0 to 4095) are NOT the type of things that someone totally unfamiliar with Block Transfers and the way that the PLC-5 handles its analog signals is going to be able to quickly figure out ... especially while the new boss is breathing down his neck and wanting to know when the machine is going to start making money again ...

this situation is not a pretty picture ... but I have seen it happen ...

so in the final analysis, the RSLogix5 and RSLogix500 software packages are certainly more “alike” than they are “different” ... and the PLC-5 and the SLC-500 hardware platforms are certainly more “alike” than they are “different” ... but still ... there ARE some substantial differences that should not be considered “trivial” when trying to cross over from one platform to the other ...

btr.jpg
 
no offense taken or intended, Ken ... but just to be absolutely correct, I said that the addressing modes are ONE big gotcha ... but I also reiterated that the Block Transfers (particularly for analog signals) which had already been mentioned by other responders were another issue ...

No problem Ron, I mistakenly assumed that the SLC user had been using Block Transfers for Remote Analog I/O because of this statement.
I know RSLogix 500 very well


I was thrilled when they added Block Transfers to the SLC's (series C or higher), made remote non-discrete I/O much easier to deal with.
 
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One neat instruction that the SLC500 has, but PLC5 do not is the SCP (scale with parameters).
It has to do with that in PLC5 scaling is supposed to be done in the analog module, whereas in SLC500 the analog module uses a raw integer value and the user must scale the value in the program.
As you can use the SCP instruction to many other things, I am mystified as to why AB didnt put it into the PLC5 as well.
If you need SCP functionality in the PLC5 program, you will have to program your own CPT function.

Other differences:

The PLC5 will not fault if the math overflow trap bit (PLC5: S:10/14, SLC500: S:5/0) is set.

You can assign priviliges and access rights in a much more targeted and flexible way in the PLC5 than in the SLC500.

edit:
Oh I forgot. Get the little book "1785 PLC-5 Programmable Controllers Quick Reference". (pub 1785-7.1). It has all the important little bits of information that you will need (not just instruction set, also the critically important explanation of the various dip-switches) in a handy pocket book format.
 
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