Logic check.

Jasondelane

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Mar 2015
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Florence sc
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I'm doing the programming for a new piece of equipment we're installing in the mill. I'm only adding logic to an existing program. This is the most programming I've done (I mostly do troubleshooting and process improvement). Can someone check this routine and let me know if it looks kosher?

This logic is meant to control a log deck, two reception conveyors, a bump stop, log clamp, saw, and log loader. The only thing it's missing is control for the saw stroke because I'm doing that in a separate routine once the VFD is installed.

All the physical I/O is mapped in a separate routine.
 
Jasondelane said:
I'm doing the programming for a new piece of equipment we're installing in the mill. I'm only adding logic to an existing program. This is the most programming I've done (I mostly do troubleshooting and process improvement). Can someone check this routine and let me know if it looks kosher?

This logic is meant to control a log deck, two reception conveyors, a bump stop, log clamp, saw, and log loader. The only thing it's missing is control for the saw stroke because I'm doing that in a separate routine once the VFD is installed.

All the physical I/O is mapped in a separate routine.
Click to expand...

Man, really ? You want somebody to check your programming for a piece of moving machinery without knowing ANYTHING about it other than your description ? Good luck with that !
 
Honestly I just wanted to check and see if there was anything obvious I may have missed to make the logic cleaner or more efficient. I'm sure there are some programming best practices I may not know about that someone may recognize.
 
Does it match similar logic in your mill?
Do you have a co-worker who knows the process talk it through and check it with you?
Can you stop the plant if it does not work the way you think, before it breaks?
Can you check each individual item moves in the way you expect?
Can you do a simulation of the logic with the motive power switched off?

If the logic works in the way that you require, then it should be OK.
Everyone writes logic differently - some make it "smart", others make it simple so it is easy to follow for anyone, or even yourself a few months down the line when there is a call to a fault, or to make a minor change.
And, no I have not looked at your logic in detail.
 
Not criticism just an observation... I'm not a fan of Latch/Unlatch stepping. Without seeing other parts of your logic what happens if a step is latched and you loose power? What I mean by that is what happens on power up?
 
The first issue I notice personally is seeing the word 'SAW' and using latch bits.

I'm not a fan of latching. Latch bits should only be used when you EXPECT something to be retained when you cycle power to the machine.
 
Last edited:
My criticism is that I don't see too many comments in the program.
It's a good habit to have as much documentation as possible, including rung comments.
 
if you are not sure about it why not pay somebody to come in and help you and teach you what you need to know. That way you get a system that you know works and you get to learn from them so the projects you will be handle it yourself
 
GaryS said:
if you are not sure about it why not pay somebody to come in and help you and teach you what you need to know. That way you get a system that you know works and you get to learn from them so the projects you will be handle it yourself
Click to expand...


+1 on that. Good idea.
 
I can't comment on how well it will work, but the program seems to be laid out well. I like the tag naming structure, and the descriptions, and don't think additional rung comments would be needed. I really like the diagnostic rung. I wish that was something used where I work.


Bubba.
 
I appreciate all the input. I went back and removed all the latches, except on alarms. It was interesting how it changed the overall routine. I put some more in depth comments on the rungs also.

Again, I appreciate the constructive criticism.
 

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