How to read and understand PLC program

[MarkNightingale]

Thanks, Jeebs, I atempted to open a file froma Panelview the other day and found I don't know how! It had a .pva extension, if I remember correctly. Does RSLogix open them? If so, it was not cooperating the way I was trying it. SO much to learn... But I sure apreciate the tips and encouragement, thanks tons!

Dale,

You cannot open a panelview program using RSLogix. You will need panelbuilder software for this.

If like others have said you can post the RSLogix file and the .pva file (zip them first) there are people here who will help.

Mark

 

[Dale_z28]

ok, I've filled in all the I/O on one program. It does look better when I view the ladders. Still alot of B3 files and timers that I don'tunderstand yet, but I see progress. Ill do another program tomorrow in my "spare time"

 

[Dale_z28]

my first attempt "commenting"

here is how I spent part of my day. I'll do another (this is 1 of 5 machines that will have very similar programs).

 

[Dale_z28]

Panelview program for same machine

I should have attached this file to the other post, along with the .rss file. I haven't opened this since we don't have panelbuilder software yet.

 

[Andy6]

Dale,
You are correct about my typo on my last post, it should have said "Output"

And after looking at that program, wow, you picked a toughy to cut your teeth on.

PS: the screen.zip file you posted is only the shortcut, you didn't attach the actual file.

 

[Ron Beaufort]

the program that you posted includes a PID (Proportional Integral Derivative) instruction ... many people consider that to be the "deep end of the pool" for RSLogix500 programs ...

I was working on a lesson for an upcoming customer's class and their basic PID logic is pretty similar to yours ... so I went ahead and knocked out a PRELIMINARY flow chart to help you follow how the signals flow through that particular part of your program ... note that I've had to make some ASSUMPTIONS – and there will be MORE EXPLORING to be done – but this should give you the main ideas as to where the PID-related signals come from – where they go to – and what makes them move ...

when you start working with the analog signals, you'll need the following pages from the manual linked below ... these can be confusing until you get used to them - so I've highlighted the information that I "think" you're going to need - based on what you've posted so far ...

1769-IF4 analog input module page 3-11 ...

1769-OF2 analog output module page 4-12 ...

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1769-um002_-en-p.pdf

good luck with your project ...

.

 

[Dale_z28]

Thanks Ron. I'll have to study this for awhile. My circuit consists of a prox switch looking at the edge of a 5" diameter notched disc that rotates as the machine raises and lowers. The signal goes to an input on the (PLC) base unit (which I belive is also a counter?). from there... I've lost it. I don't have software to get into the panelview,and don't see it in the PLC program after it's listed as an input.

 

[Lancie1]

The signal goes to an input on the (PLC) base unit (which I belive is also a counter?).

The PLC input terminals may be only a standard digital input, but inside the PLC program, there could be a Counter or a High-Speed Counter that counts the ON/OFF input pulses.

 

[Ron Beaufort]

don't worry about the PID stuff I posted – until you need it later ...

the main reason that I offered it to you was to demonstrate a SYSTEMATIC method for tracking signals from an INPUT – through the program LOGIC – to an OUTPUT ... that type of approach is quite often the secret handshake to working your way through a convoluted program ...

as for the signal you just mentioned, it sounds like you're using the High Speed Counter features ... see if the rungs below are a piece of your puzzle ...

.

 

[Dale_z28]

Dale,
You are correct about my typo on my last post, it should have said "Output"

And after looking at that program, wow, you picked a toughy to cut your teeth on.

PS: the screen.zip file you posted is only the shortcut, you didn't attach the actual file.

Heres the file (I hope!)