PLC installation regulations

alanze

Member
Join Date
Jan 2019
Location
Kentucky
Posts
40
I have a bit of a weird question. I'm finishing my degree in mechanical engineering, and as part of my capstone project we're working with a company to design and build a machine that will need a PLC. I have about a year of experience with PLCs, but mostly just programming them. Sometimes installing new sensors to existing PLCs.

The machine is relatively small rinser / dryer for brass cartridge casings for ammunition. We really haven't done much designing yet, but we have access to 480 and 240VAC. I assume we'll need 480 for a motor and heater as part of the drying mechanism. The question isn't about the design, but really about installation regulations, especially since I've never installed a PLC before. The company is small with only a couple engineers, none of which have experience with PLCs. One of the engineers suggested programming the machine with an arduino, but I feel like thats not reliable longterm. Not to mention its more difficult to program compared to ladder logic. This company doesn't even have a licensed version of Logix 5000 to edit their current machines. I can probably setup a new PLC following manuals from rockwell, but I personally don't want to mess with high voltage. Are there any other regulations I should be aware of? I figure we'd need to hire a professional electrician for the motors at least. I guess I should mention that the machine will be built and used in Kentucky. Any insight would be appreciated.
 
If it's a new system I'd select 24V DC as your control voltage. Much more common to find modern PLCs with 24V digital inputs and outputs.

A small DC switch mode power supply is all you need for that.

It sounds like you need to get a proper panel shop involved to build your control panel, once you've figured out what you need in terms of I/O, controls, motors and sensors etc. That is by far the safest way to do this, then have a licensed electrician wire it up. Plus, ask them to do the wiring schematics.

Even if this is just a prototype, it still needs to meet relevant code and safety standards.
 
First I agree with Saffa on the 24v for panels (it just makes life easier to not have to LOTO for simple troubleshooting issues).

Second... I wouldn't go with Rockwell unless you can get Rockwell to sponsor your school project. The sunk costs are just too high (while you have alternatives). Arduino is a solution... but if this is for industrial, don't use it. I feel you just have too many unknowns for me to give solid advice on the best path forward.

I love creating projects from scratch and love revving them up to better more standard projects. I feel I don't know enough to give you a solid path forward. I know what I would do, but just explaining using ethernet for +24v devices requires a min. understanding. (You can do it, and make it work but it may end up being really unsafe. For example, people that run normal ethernet cable when they should have 600v rated cat cable.)
 
Welcome to our favorite profession !

What part of Kentucky are you in ?

If NFPA 79 and UL 508 aren't part of your everyday vernacular, you need to seek out a local industrial control panel shop to build this control panel for you. Every industrial control panel needs to be built to the appropriate code standard, which for most stuff is NFPA 79, Electrical Standard for Industrial Machinery.

If you aren't tied to a specific vendor, ask which one they're most familiar with. A MicroLogix or S7-1200 or a CoDeSys based controller would likely do the job.

Be wary of this forum's tendency to throw recommendations like "this is my favorite controller so it's what you should use as well" or "here's how I would do this for the absolute minimum hardware purchase cost, regardless of the functional, expansion, and maintenance requirements".

In my opinion, for one-unit machines the cost of the PLC should not be your guiding factor, but rather your ability to use it to solve an application, and the ability of the people in your company and community to work on it if you win the lottery.
 
I'm in Hardin County, KY. I kinda figured it would be bad idea trying to build our own panel since I dont have experience, plus I dont know NFPA 79 and UL 508. I assumed we'd go with Allen Bradley since their other existing machines use CompactLogix L18ERM. The only issue is they dont have a license for Logix 5000 which would add cost. I was honestly looking at adding some more IO to the other existing PLC, but they prefer it to be a standalone because they want to ability to move the machine in the near future.

Without a copy of logix 5000, they can't make edits to their current machines. They also dont have experience with ladder logic, but I'm trying to convince them to get a license for it. There are some simple changes they would like to make to their current machines that would be easy with logix 5000. I was looking at the different packages and I wasn't sure which version they would look at? Would LITE edition be the way to go since it's the cheapest?
 
...Would LITE edition be the way to go since it's the cheapest?


Not if you mean RSLogix Micro Starter Lite: that only works on some MicroLogix 1000 and 1100 hardware.


CCW works with the Micro8xx line, and is free, IIRC, but I am pretty sure it will not work with ControlLogix and CompactLogix.

What hardware do they have?


Caveat: very little experience, but that is my understanding from listening here and reading a lot.


My brother you may be able to do it better than A-B, but you can't do it more expensively.
 
I think the mini edition is actually the lesser as the lite includes the advanced language packages for FB and ST, SFC. This will likely be ~500$ or so really depends. 500, 5000 Seem to be favorite numbers at Rockwell.

Mini Catalog #9324-RLD200ENE
 
Ah I hadn't even seen the mini edition. That might work well since I plan on only using ladder logic, and it appears to work only with compactlogix.
 
My two cents having built a kazillion machine panels. Check out the Koyo Do-More PLCs and C-More HMIs at Automation Direct. The products are bullet-proof and the software is free.

Agree with everyone else that you should just use 24 Volts DC for your controls. Also agree that if you're not familiar with electrical and machine codes, you may need some electrical help building this. As you already have experience though you should be able to program this.

One thing that you didn't mention - the dryer is going to be what kind of heat source? Electrical, Gas, fuel oil? That can open up a whole other world if you need combustion control.
 
Be wary of this forum's tendency to throw recommendations like "this is my favorite controller so it's what you should use as well" or "here's how I would do this for the absolute minimum hardware purchase cost, regardless of the functional, expansion, and maintenance requirements".

In my opinion, for one-unit machines the cost of the PLC should not be your guiding factor, but rather your ability to use it to solve an application, and the ability of the people in your company and community to work on it if you win the lottery.

I don't know how your senior project went but I remember we had a max budget of $5000 dollars. If just getting the PLC and software for PLC eats that up... not much point in continuing the project. (I didn't even include an HMI or buttons, let alone IO cards and all the other stuff needed to make it right.)
 
I don't know how your senior project went but I remember we had a max budget of $5000 dollars. If just getting the PLC and software for PLC eats that up... not much point in continuing the project. (I didn't even include an HMI or buttons, let alone IO cards and all the other stuff needed to make it right.)

While that is true for smaller in-lab projects, sometimes if it's just a service the students are providing to the company, buying "tools" like Logix5k might be an option.
 
My two cents having built a kazillion machine panels. Check out the Koyo Do-More PLCs and C-More HMIs at Automation Direct. The products are bullet-proof and the software is free.


My 2c. I have found Koyo used a lot in smaller companies for small machines. Many small are start ups and an expensive PLC takes a lot of payback out of the machine.
 
My two cents having built a kazillion machine panels. Check out the Koyo Do-More PLCs and C-More HMIs at Automation Direct. The products are bullet-proof and the software is free.


My 2c. I have found Koyo used a lot in smaller companies for small machines. Many small are start ups and an expensive PLC takes a lot of payback out of the machine.

I can't argue with using the Click and the DoMore PLCs. We have about a dozen Clicks clicking away and some are in terrible conditions. Years later, no failures, and if one of them does die, replacing it will cost less than a digital input card from big brother.

Last fall I installed 3 DoMores in a solar application. The learning curve made the cost savings less optimal but after getting familiar with DoMore, I will definitely use them again.

I am not a fan of the PSuite gear. I have 4 of them in the field and there are some things about the software and hardware that I cannot stand. I have had multiple failures of I/O cards, and loss of allegedly retentive data that has cost me. I won't use PSuite hardware in the future. If they started counting bits at 0, and got rid of the extra useless "initial data" and made retentive data actually work right I would reconsider.
 
I've used a lot of Click Koyos and found them very reliable and very cost effective. If budget is your biggest constraint I'd definitely view that as a viable option.

However if you can stretch the budget to a copy of Logix 5000 Mini, there are obvious advantages to you with being able to support your existing machines as well. A 1769-L16ER-BB1B is relatively cheap and very capable - certainly not as cheap as a click koyo, but much more capable.
 
A little sidebar. I programmed a shift break buzzer for a weld shop as a favor for a customer that helped us through a cluster that we as the OEM created.

They had a spare click plc and a buzzer, I powered it with an old extension cord and just wired the buzzer directly to the output.

I assumed they would put it in an enclosure and hang it on a wall somewhere. I went back to that same customer about 5 years later. The buzzer went off and I had remembered doing the job. I went hunting for it and found a completely black click plc sitting on the top beams of one of the uprights for a planet rack right in the center of the weld shop. It was still working just fine.
 

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