Subroutines: Micrologix 1500, RSLogix 500

[Merganzer]

Hi,

Working with an AB Micrologix 1500, RSLogix 500 programming.

I'm trying to write subroutines to control a 3 floor elevator system. Main program file will direct the PLC to a particular subroutine file when a particular floor button is pressed (ie.: 3rd floor goto button sends PLC to 3rd floor subroutine).

The problem I am having is that it doesnt seem like the PLC likes to unlatch bits within a subroutine. Im setting a bit within the subroutine to start my drive at 60Hz, then unlatch that bit at a certain point and latch another bit to change the drive to 35Hz. The drive will contine to operate at 60Hz even though there has been an input to unlatch that bit.

Suggestions?

 

[geniusintraining]

Merganzer,

Can you post your program? it may be better that way

 

[Merganzer]

will do, just give me a few.

 

[Merganzer]

im kind of a noob, how do i post the code?

 

[jimcav]

check this out

i will post a program check out how i use a timer in the main to control which subrotine is used.

 

[504bloke]

im kind of a noob, how do i post the code?

take your logix file *.rss and zip it up (winzip or something similar)

Then when you make a post, look down below the list of smilies in the typing box and click attach files

 

[Merganzer]

heres the ladder file

 

[Merganzer]

I dont have a sweet clue what your trying to do in that PDF file.

 

[geniusintraining]

I'm having PC issues...but at first glance you are droping out your sub when your call your speed? I can't print the PDF...


Look at this closer

 

[504bloke]

To start with you have mulitiple OTE's

O:2.0/3 referenced OTE in both rung File 4 Rung 1 and File 3 Rung 0 give one example of this.

As far as i know thats a big no no on AB with the OTE.

Do a search here on multple ote as i am sure it has come up before

 

[Merganzer]

Well, I dont exactly understand your question, but are you saying that having the load-invert for Down 60Hz at the top of LAD 2 is screwing up my subroutines?


I placed those there so that the other call/goto buttons would be inactive while the elevator is moving (because I havent set up the programming yet to store a sequence value).

 

[504bloke]

Another Multiple OTE instance is O:2.0/1.

Looking at the code quickly i would imagine there are a few of these instances with each up down output bit ?

 

[504bloke]

Pdf attached of the rss file for Terry

 

[geniusintraining]

In U:3 you set your output 0;2/3, when you do this (on your next scan) U:3 will go low...one thing at a time do what Dave is talking about first, I need to work on my PC

 

[Merganzer]

Yes, the outputs for the drive are in multiple locations because the elevator must travel up for the 3rd and 2nd floor and down for the 2nd and 1st floors. Instead of having subroutines for individual floors, would it be a better idea to have subroutines for separate speeds? This would limit the OTE location to one.