Newbie RSLogix 5000

Hey guys great site! Anyway I'm working temporarily over my winter break for a company. Basically I just get to mess with some of their plc control systems. I graduate in May, and this could lead to a job! But I do have some questions reguarding RSlogix 5000

Background-
I took a class last semester, we messed with micrologix 1000s, SLC 500s and of course RSlogix 500. I have an understanding of ladder logic, inputs, outputs, timers, counters, sequencers and bitshift operations.

Now at work I'm playing with RSlogix 5000, and I understand the tags (for the most part) and I have inputs, outputs, timers, and counters all figured out. My next step is a sequencer. Which leads to my confusion.

What part of the sequencer is actually tagged? The array?
Where is the sequencer file stored? How can I change it?
How is the destination setup? (ie if I just want to turn on outputs)
The mask looks to be setup the same as in RSlogix 5000 correct?

I've been searching google like crazy, but everything I find have to pay for.

Thanks in advance!

Look here:
http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1756-rm003_-en-p.pdf

Thanks for the link! Got it figured out!

Sequencer advice:
Unless you Absolutely Positively Need to use a Sequencer (as in, it exists in some code already) stay away from them.

Especially in Logix5K, I'd rather use SFC than a sequencer, or just ladder for that matter.

Personal opinion, yours may be different, but Sequencers are a royal pain in many unmentionalble parts when it comes to troubleshooting or maintaining them.

Agreed. SFC is superior to a sequencer.

As a general rule, I do never drive an output direclty with the sequencer. I will point the sequencer output to a DINT tag and then use bits from that tag to turn on the output from another rung. I will include critical interlocks on that rung as well even if t hey are duplicates and/or are accounted for in the sequencer logic. It enhances program readablity. When someone comes along to troubleshoot whatever they expect to see turned on the first thing they are going to do is search for the output address in the program.

I'm not writing any important programs at all, because I have already learned/used sequencers in 500, naturally I want to know how they work in 5k. I'm just working on getting a solid foundation of how the various functions work, as I learn more, I'm sure I'll realize that there are better ways to perform operations.

Now that I have a general understang of how sequencers work, time to check out the bit-shift functions!

On a side note: JSR functions, are these used mainly to keep a program organized? Similar to function calls in C++?

Paully's5.0 said:

On a side note: JSR functions, are these used mainly to keep a program organized? Similar to function calls in C++?

Click to expand...

The most common use of JSR in the cyclic task is indeed to call other routines in order to structure the program better.
I find many, small, appropriately named routines easier to design, program, and later troubleshoot than one huge ladder.
JSR's in this case are generally unparameterized.

To further aid my organization, I generally name the lower level routines with underscores, a number, and the basic function name:
_001_First_Scan
_010_Interlocks
_020_Alarming
_030_Payoff
_040_Slitter
etc.

That just prevents Logix5k from insisting on putting things in alphabetical order in the project tree.

JSR's can also be parameterized; where you actually pass values to a subroutine, and return them from a subroutine. These are commonly used for implementing 'pseudo-user-defined-function-blocks', like a generic motor starter control, or maybe an MOP function that would be used many times in a program.

Be careful with parameterized JSR's.. make sure the code block is truly generic, and absolutely debugged. It is nearly impossible to debug a parameterized function that is called from many places.

JSR's can also be used on conditional rungs to only execute certain blocks of appropriate code... ie, call the 'Automatic' routine if the system is in 'automatic' mode, and the 'Manual' routine if it isn't.

Question about analog output on Logix 5K

I am a beginner so i don't know a lot about programming yet. I was hoping someone can give me advise on programming an analog output (4-20mA valve) that will be controlled using a 0-300 PSI transmitter. When the transmitter reaches a certain psi the valve needs to open accordingly.

bklassen322 said:

....I was hoping someone can give me advise on programming an analog output (4-20mA valve) that will be controlled using a 0-300 PSI transmitter. When the transmitter reaches a certain psi the valve needs to open accordingly.

Click to expand...

"to open accordingly" is a bit vague, but it sounds to me like you want pressure control using the analog output. For that scenario, you will most likely want to use PID control, so that the pressure is regulated at the setpoint.

However, if it is just pressure relief you need, then you probably don't need an analog output to drive the relief valve, just open a solenoid valve until the pressure falls below the setpoint.

Wow when I first started reading this post I was really confused. I know Paully is not a newbie so I couldn't figure out what the hell was going on. Then I looked at the date of the first post and it made sense.

bklassen 332: I know Daba has replied but it is always better to start a new thread than to tag on to a 13+ year old thread. It makes the flow of things better and much easier to find in a search if you ever need to find out the answer again.

BTW Welcome to the Forum!!

Guilty !

It came up as a new post, didn't look back to see how old the thread was, but I hope I gave bklassen322 an answer relevant to his scenario....

Ok. It is for pressure control so I will use a PID Loop. I am just not sure how to scale the analog in for the PID block. Also the scale for the output. Sorry about posting on this thread, I wasn't quite sure how to navigate yet.

Bullzi said:

Wow when I first started reading this post I was really confused. I know Paully is not a newbie so I couldn't figure out what the hell was going on...

Click to expand...

You and me both! Fudge, 13 years ago...pretty sure our Smilies are still the same