PLC 5 and SLC 500

Chakija

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Join Date
May 2003
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I'm totally new in working with AB PLC-s so don't resent me if my questions are a bit silly.
Can someone briefly explain to me the difference between SLC 500 and PLC 5 series? What are the performance and capabilities differences, and very importantly what are the differences in prices? Do they use the same software for programming? I know that SLC 500 uses RSLogix 500, but what is used for PLC-5?
 
I was cruising around the internet a few nights ago and I stumbled on this website .
I hope it helps you with your problem. ;)
Anyway, RSLogix 500 is for SLCs series, and RSLogic 5 for PLCs series.

Regards

Sherine Tang
 
Well....
If we compared them to automobiles, the PLC-5 is a large dump truck.
Used on large jobs. The SLC is a pick up truck, good for small to medium sized jobs.

The big difference in the two is number of I/O supported and processing power. The PLC-5 can support many, many, many times the I/O that a SLC can. The SLC basically has one processor that does everything, and the PLC-5 has multiple processors with dedicated task, such as communications, ladder, etc...Plus the PLC-5 has many more instructions than the SLC.

There is a place for both, many times using a PLC-5 would be overkill, where the SLC is just the ticket

PLC-5 requires RSLogix 5 for programming.
 
As Ken said - the PLC-5 is a much more powerful processor which gives faster scan times and the ability to use more I/O.

One minor difference that hasn't been mentioned is in I/O addressing - the PLC-5 I/O is Octal based where the SLC is Decimal based.


Good luck,

Marc
 
and digging a little bit deeper ...

as for price ... as a basic salesman's rule of thumb:

the cost of automating a certain application with a PLC-5 would be about THREE times as much as it would cost using the smaller SLC system ...

also ... the PLC-5 is a much heavier "industrially hardened" looking animal ... lumber mills, paper mills, steel mills, etc. often feel more comfortable with something “heavier” that their technicians can "work on" ... the smaller plastic cases of the SLC often leave "manly-men" like Bubba the maintenance tech wanting something with a little more "meat on its bones" ... of course that's just a perception thing ... neither of the platforms is designed to be abused ... but still the "heavy-duty vs. light-duty" topic does come up from time to time ...

and besides the "octal/decimal" addressing issues ... the PLC-5 supports "two-slot" and "one-slot" and "half-slot" addressing modes for its local I/O ... SLC users don’t need to worry about those topics until (unless) they start working with a remote I/O chassis ...

and a BIG one ... for analog signals ...

the PLC-5 system uses Block Transfer Reads and Block Transfer Writes to communicate with its analog I/O modules ... and the analog signals are addressed in an integer-type file ... MOST analog signals with the SLC system do not require Block Transfers ... and the signals are addressed on the Input and Output tables right where most people expect them to be ...

finally ... for customers that have BOTH systems (PLC-5 and SLC-500) then I recommend that they study the PLC-5 first ... it’s like learning to drive a “clutch pedal and stick shift” car ... the SLC is more like an “automatic” ... it’s generally a lot easier to cross-train from working on the PLC-5 to the SLC rather than the other way around ... that’s not to say that the SLC is more “user friendly” or makes it easier to write a “traffic light” program or something like that ... it’s just that the PLC-5’s extra addressing schemes and its analog signal handling techniques require quite a bit more “study” than the SLC ...

as for software prices ...

RSLogix5 for the PLC-5 platform was going for about $3,500 the last time I checked ... RSLogix500 (full-package) for the RSLogix500 was about $1,100 ... note: for people who need BOTH, ask your distributor for the "bundle" price ... last time I checked that could save you $400-$500 or so ...
 
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