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Old October 18th, 2018, 09:10 PM   #16
TheDude_Abides
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I am fairly new to programming so this will be something to build on. I am familiar with intergers and what they do but Ive mostly just been programming ladder logic. From a quick good search it does seem to make navigating easier but there seems to be a learning curve.
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Old October 19th, 2018, 08:58 AM   #17
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[quote=TheDude_Abides;794897]Currently the Estop is wired in series with the line voltage for the PLC. However, now that I think about it it may be better practice to have the Estop reset the cylinders in case of a pinch injury.

I would have a real problem with this one!!!

Sounds like this machine is a death trap! The E-Stop should be wired to a safety circuit. Not the PLC line voltage, that is ridiculous.
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Old October 19th, 2018, 09:11 AM   #18
sparkie
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Man, I would like to know what integrator did this work.
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Old October 19th, 2018, 10:56 AM   #19
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Guys, with all do respect. Im not asking for judgment to be passed let alone criticism. I've recently taken over the electrician job and I only have so many hands. alot of equipment here is lacking plenty of safety equipment. I am trying to implement as much as I can in a little amount of time. there are so many hours in the day.
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Old October 19th, 2018, 11:00 AM   #20
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With that being said, would anyone mind taking a look at the program I just rewrote for this and let me know if you see any discrepancies? If not, its totally understandable. I'm trying to learn through this whole process and any helpful advice from experienced personnel would be genuinely valued.
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Old October 19th, 2018, 11:03 AM   #21
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[quote=PLC Pie Guy;794926]
Quote:
Originally Posted by TheDude_Abides View Post
Currently the Estop is wired in series with the line voltage for the PLC. However, now that I think about it it may be better practice to have the Estop reset the cylinders in case of a pinch injury.

I would have a real problem with this one!!!

Sounds like this machine is a death trap! The E-Stop should be wired to a safety circuit. Not the PLC line voltage, that is ridiculous.
This is a very old plant with the last electrician having been a dinosaur with very old school line of thinking. Ive been in several cabinets, namely a natural gas furnace where the safety relay was completely unwired and a bundle of wire nuts on all the wires from said safety relay nestled underneath it in the wireway. Needless to say the furnace was shutdown immediately.
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Old October 19th, 2018, 11:47 AM   #22
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That's very good work, simplifying the original programmer's mess of latches.

Abstracting the digital inputs into their own subroutine is a very good practice. It also gives you a place to add "debounce" timers if short or inadvertent triggers of a sensor are a problem.

The two sensors I would add a delay timer (maybe 50 to 100 ms) to are the Foot Switch and the Setup/Auto selector. Just use the input point to run a TON timer, and use the /DN bit of the timer to run your internal sensor status bit.


I don't recommend the method you used to run the Setup and Auto mode subroutines separately, because when you stop executing a subroutine, the outputs stay in their last state. It's not a huge deal in your specific program, but it's not a method I like.

Instead, I would delete the Setup subroutine and put the Auto/Setup switch and the manual pushbutton control onto a rung branch for each output in the Outputs section.

That way the Auto/Setup mode switch becomes a simple IF/ELSE decision in the Output subroutine, rather than being referenced repeatedly in the rest of the program.

Example:
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Old October 19th, 2018, 12:02 PM   #23
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Zipped and posted: example of how I would set up the Output subroutine.

I'm still confused by the labels on the Setup/Auto switch; the label on the input itself suggests you're in AUTO mode when the input is True, but the label on the internal bit suggests the opposite.

That's one of the nice things about using an Input routine; if you have normally-closed sensors you can flip the polarity of the internal bit so that its state is more consistent with the sense of "if this boolean bit is true then this label condition is true".
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Old October 19th, 2018, 02:40 PM   #24
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Quote:
Originally Posted by Ken Roach View Post
Zipped and posted: example of how I would set up the Output subroutine.

I'm still confused by the labels on the Setup/Auto switch; the label on the input itself suggests you're in AUTO mode when the input is True, but the label on the internal bit suggests the opposite.

That's one of the nice things about using an Input routine; if you have normally-closed sensors you can flip the polarity of the internal bit so that its state is more consistent with the sense of "if this boolean bit is true then this label condition is true".
I understand. I mustve updated the bit but not the input. Thanks for that, also thanks for taking the time to examine my work. Ive been plugged in most of the morning working out the bugs. It's working 99% but the operator doesnt like the point the parts rest falls so I will be finishing that out the rest of the day.
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Old October 19th, 2018, 03:51 PM   #25
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double post
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