rslogic500 /controllogic 5500

mgomezov

Member
Join Date
May 2006
Location
defiance ohio
Posts
1
i have worked with rslogic 500ab.i started a new job they have controllogic 5000,is it similar 500 and how do they compare.i had my first look at the ladder of the 5000 and it was difficult to interpet, i/o were different can anyone explain/summarize.
 
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Once you use RsLogix 5000 you will love it, but the big learning curve is the tag database. It has no structure so you can create structure and anyway you want or you can screw up as many do and have no structure at all.

I/O is easy. Pretty much it is Local:S.X.Data.B
S=slot
X=I for input, O for output, and C for configuration
B= specific bit.

There are more specifics but that will get you started
 
Also look at the tasks closely. I am working on a machine right now that was designed and programmed by an external Engineering group. When they made the Controllogix program they made the main Task of the program as a continuous program. In RSLogix 5000 this program is run and interrupted any time another task needs to run. This was causing problems, because the main task started 7 Powerlex drives and what would happen would be that some of these drives would start and then the main task would be stopped and the other tasks would be ran. What I did to correct this was make the main task a routine task with priority 5 and the others with a lower priority. This make the main task the highest priority so nothing can stop the task in midstream.
 
I would strongly recommend taking an instructor-led course from Allen-Bradley. A few years ago when I first started looking at the ControlLogix I decided to take a course, and was glad I did. My previous knowledge of PLC-5's and SLC's came mostly from self-teaching and interacting with other engineers, but since I had the time I decided to take my first A-B course.

It appears that the courses have changed since I took it, but if you ask your sales rep I'm sure they will direct you to the course that is appropriate for your experience. The courses are not cheap, but so much is different with the ControlLogix that in the end it will save you a lot of time and frustration.

Don
 
Another thing to know abou the L5K line is that the IO is asynchronous to the program scan. Unlike the SLC the modules are configured with an update rate which can occur mid scan rather than at the beginning/end of the scan as with the SLC. This has advantages and disadvantages, but for 99% of the apps it simply won't matter.

The UDTs are very powerful and enable object oriented programming which can be a huge time saver as your library grows.

The Logix5000 family is cheaper than the PLC5s and the Compact Logix is very inexpensive, way less than a SLC with twice the power - so much so that we will do no new projects with the SLC500 line.

Once you get used to the L5K you'll love it.
 
Logix5000 is the best PLC programming software I've ever seen. Custom data types are so awesomeeeeeeee! :D I go crazy with them. You can even write custom instructions.

The tag database is the hardest, and the I/O tree can be a bit confusing. But if you are used to AB already, you shouldn't have too much problem getting used to it. Just don't be scared of it.

Read the Logix5000 Controller Common Procedures manual, it will give you a lot of help getting started, and its extremely useful for a beginner. http://literature.rockwellautomation.com/idc/groups/literature/documents/pm/1756-pm001_-en-p.pdf

$
 
Moltra.
Have a good read of the manual on tasks. What you are saying does not quite make sense on the way continuous and periodic tasks functions.
Regards Alan Case
 
moltra said:
Also look at the tasks closely. I am working on a machine right now that was designed and programmed by an external Engineering group. When they made the Controllogix program they made the main Task of the program as a continuous program. In RSLogix 5000 this program is run and interrupted any time another task needs to run. This was causing problems, because the main task started 7 Powerlex drives and what would happen would be that some of these drives would start and then the main task would be stopped and the other tasks would be ran. What I did to correct this was make the main task a routine task with priority 5 and the others with a lower priority. This make the main task the highest priority so nothing can stop the task in midstream.

I should have said Periodic Task instead of Routine task

From AB Common Procedures manual for RSlogix 5000.
Publication 1756-PM001H-EN-P - June 2005​

Section 3.2
Continuous Task

The continuous task runs in the background. Any CPU time not allocated to other operations (Continuous such as motion, communications, and periodic or event tasks) is used to execute the programs within the continuous task.

- The continuous task runs all the time. When the continuous task completes a full scan, it restarts immediately.

- A project does not require a continuous task. If used, there can be only one continuous task.



Periodic Task

A periodic task performs a function at a specific period. Whenever the time for the periodic task expires, the periodic task:

- interrupts any lower priority tasks

- executes one time

- returns control to where the previous task left off

You can configure the time period from 0.1 ms to 2000 s.

- The default is 10 ms.

- The performance of a periodic task depends on the type of Logix5000 controller and on the logic in the task.

 
Hi, What I am having a hard time following is the following. The continuous task starts 7 drives. Therefore the start sequence may be interrupted to allow a periodic task to run. The continuous task will then continue from where it left off, at whatever time it took the periodic to run (maybe 2 millisecs later). How can starting 7 drives require an uninterupted start sequence?
It is possible to schedule periodic tasks so frequently that there is no time left for the continuous task, which will also cause task overlap in the periodic.
Also note that periodic tasks can be interrupted, by comms, event tasks or motion commands so it is hard to get a continuous program execution, but you should not need it, for a motor start sequence.
Regards Alan Case
 
I have seen code that did error checking and or alarming in another task. If you do this and have a lot of scan dependant code it can cause problems.

Worked great at commissioning then code gets added making scan longer and an occasional task overlap induces alarms and faults. This is all avoidable IF you understand the sequence of operation for a ControlLogix.

If you have any doubts about the scan sequence or priorities of event or periodic tasks then you are probably better off putting all the code in the continuous task.

CLX's are blazing fast, it is rarely a problem with the actual scantime. It is usually a problem with the programmers understanding of the task execution model.

I agree with Alan regarding starting motors in a continuous scan. In most applications that should be no problem. The only way I can think of for that to cause trouble is scan dependant logic or task overlaps. Which can both be avoided.

Moltra I understand what you did to correct the problem you were having. It's just that it really should not cause a problem if the code is written taking into consideration the way a CLX works.

RSL
 
One problem with the code that I did not mention before was that one routine the speed ramping task was set to run at 1ms. It was overlapping itself and stopping the continuous motor starting task every 1ms. The Machine is a vertical conveyor loop. If one of the 7 motors does not start at the same time, the material (rubber) on the conveyor would jam up.
 
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mgomezov said:
i have worked with rslogic 500ab.i started a new job they have controllogic 5000,is it similar 500 and how do they compare.i had my first look at the ladder of the 5000 and it was difficult to interpet, i/o were different can anyone explain/summarize.


comparing 500 to 5000 is like comparing Win95 to WinXP. While most functions are similar, 5000 is a better set-up. Check the manuals (RTFM?) for 5000 & talk to your local rep.
 

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