Classes on PLCs?

Electronics
#21

By all means, if you want to teach a class on PLCs, do so.

At the end of the class, kindly teach the students that when they need to do control systems that need to respond in the microseconds, and process massive amounts of data throughput in real time, that PLCs are worthless, and different means have to be considered.

I don’t know if you could tell by now, but I’ve never been a big fan of PLC technology. It’s dumb tech, for dumb problems, and that’s cool, for it’s own dumb reasons.

Seriously, we are in an era when an elementary school STEM child can design a better system than a PLC solution, and make it work for 1/100th the cost. Where do you honestly believe this will lead?

#22

You’ll get no argument that sub millisecond response and high data rates are not good use cases for PLCs, but no one is advocating for a PLC if those are your requirements.

PLCs get used because they offer solutions to problems that other options don’t address. Just because those solutions aren’t obvious or aren’t applicable to your use case doesn’t make them dumb, it just means they aren’t meant for you.

I started out in the industrial control space, using Siemens S7-400H PLCs to run drilling rigs, nowadays I do PCB design for our own in house control systems. In spite of actually being the ‘elementary school STEM child’ you talk about, designing cheaper control systems than a PLC offers, I still recognize the benefits of using an off the shelf PLC and still use them when the time is right.

#23

I didn’t intend to start a flame war with my simple question, and also didn’t intend to open the topic about which electronics design is superior.

Possibly, but those willfully dumb people own factories with assembly lines that use PLC’s and they’re hiring people to repair the circuitry. If I apply for a job with them and they ask if I have experience with PLC’s and my reply is, “No, but I know all about arduinos and Raspberry-Pi’s,” I’m probably not the person that will get hired.

I’m simply looking to learn some job skills by dealing with jobs as they are, not as they should be.

7 Likes
#24

That class sounds interesting. I’d sit in on it with you and marvel at things I don’t understand.

#25

I get it, PLCs were all the rage in the 80s and 90s for automation. A lot of those racks are still humming away in big industrial machines. When you have to troubleshoot one, you will find it fairly easy to fix, if you don’t mind paying $150 for the single module that went bad.

In this day and age, it’s IOT (Internet of Things). Not only is a machine automated, it puts up its own webpage, and can be remotely accessed for maintenance and metrics reporting. Microcontrollers have taken over the planet.

#26

I know I didn’t plan on bothering, but in the interest of the the rest of those reading the thread: this is done by a PLC, it’s HMI, and SCADA management suite… not by a typical microcontroller.

2 Likes
#27

My company builds million dollar machines. We manage and monitor them with IoT. The IoT software is collecting its data from traditional (yet very much modern) PLCs. Not Microcontrollers. At a million dollar investment, implementing a critical control component with a lifetime expectancy of a few years would be silly.

As said before, there are use cases for both. When you get to critical infrastructure and industrial markets with multi-decade investment cycles, PLCs are still king for the foreseeable future. For lighter-weight use cases, microcontrollers have indeed taken over. Properly designed IoT doesn’t care which one you used to control the machinery.

1 Like
#28

Interesting.

My company builds million dollar machines, too. We don’t outsource anything to PLCs; we use Ether to CAN Bus for control, and embedded OS for management. Since the 90s, we have saved literally millions of miles in wire by doing so.

Operators can open a call with our support, and our web enabled machines are instantly uplinked with remote diagnostics. I couldn’t imagine us ever putting an Allen Bradley PLC in one of these systems, it’s just too archaic and limiting.

The Chinese are coming, with their version of IOT. ESP32 has onboard WiFi, Bluetooth, A/D, timers, etc; and they cost only a couple of bucks. I can envision a universal controller, that you just flash with code from your smart phone. Power interface will be just as universal, stackable Mosfets and IGBT modules, just plug them on.

#29

So can either of you two million dollar machine guys get me a job?

10 Likes
#30

Holy mackerel. Such vitriol for what was otherwise an interesting thread. If we did a show of hands (I didn’t seen emoji for that), Jim get my vote on all counts.

5 Likes
#31

This post was flagged by the community and is temporarily hidden.

#33

@Terrence what are your skill sets? Have you done any controls work before? The Controls companies are always looking for folks to hire. Most deal with BACnet, Modbus, some dare I say Lonworks (I dislike that protocol)

#34

Man those building automation people are weird.

Profibus/net, Devicenet, and a few flavors of modbus are what I would see in the oilfield.

#35

I’ve been seeing totalflow recently, and still followed up by morbus and “Ethernet/IP” (not to be confused with actual ethernet and IP)

#36

Lonworks sucks. You have to pay for credits to download controllers. Of course there are different flavors of each. IE Bacnet has MS/TP, Ethernet, IP, ect. Then there is Proprietary protocols & proprietary BACnet objects

#37

Yall are all wrong, fight me.
Until you’ve actually had the ludicrous pleasure of building a processor from scratch in Visio or every wire and transistor by hand I don’t want to hear it.

It’s best to just build entire processor Arithmetic Logic Unit, Memory & Registers out of NAND logic gates. AND, OR, NOR, NOT & quantum whatever gates are for the weak and lazy.

I’ve included one I designed 15 years ago in Visio for computer architecture. Go print it out on CA’s wide format printer. Then go use lithography in printmaking to put it on silicon glass youve created out of sand in glass works. Run over to electronics to steal all of Art’s wires, resistors & capacitors. Skip over to metal shop to build a faraday cage to put it in. The finally Hop into the Resin SIG cabinet & to pot the whole thing and encase it in epoxy. If you have trouble with the digital files go to digital media to edit them. As always feel free to use logistics general use tables and the automotive loading ramps to get it in and out of the building.

Now that thing will outlive all of us plus nuclear war and EMPs without even flipping a bit.
It’s basically its own time capsule.

This is a makerspace damn it, stop internet arguing and just build something.

Tired of compute splaining to you nerds.
Attached are DXF, Visio, PDF, SVG & JPG versions

Happy Thanksgiving as an Easter egg I’ve removed one wire for you to find.

Let me know if you finish and want to get to “Phase II” :open_mouth:

& for the love of god can an talk admin please enable some kind of vector graphic file attachment and loosen up the file size limit a bit.

image
image.png893×178 10.9 KB

image
image.png3552×1957 724 KB

2 Likes
#38

I haven’t even had my third plate of turkey yet, so I’m not even ready to get the Christmas tree out of the attic. Easter?!? One holiday at a time, man!

And as for your Visio processor design… I’m at a loss for words. That’s at least worth a few kudos…

3 Likes
#39

Sorry for the delay replying, I took some holiday time away from the computer.

Skill sets. Here’s a partial resume’. I was in the Navy 6 years as an Electronics Technician and was a Reactor Operator on a submarine, where I got a lot of general experience repairing discrete electronics doing control and monitoring of the reactor and the reactor primary. It also included some work with fluid flow, pneumatics, hydraulics, and electrical distribution including generators, motors, pumps, valves, and some water chemistry thrown in.

After getting out in 1983 I worked on bank equipment for 33 years including pneumatic tube systems, alarms, CCTV, and did ATM work for the last 16 years. Included in that is working on mechanical and electronic combination locks and key locks for bank security equipment.

Along the way I took up computer hobbyist stuff all through the 90’s and worked on hardware, no programming. I’m probably not far from having A+ cert. knowledge level but never took the time to actually get the cert.

Then I tried retiring in 2015 but got a job making side money first driving auction cars, then driving passengers for therapy.

Now I’m coming out of retirement and looking for a full time job. I can move if needed but prefer the north Texas area.

3 Likes
#40

I have some spare PLC units and the software needed. I was at the MS yesterday wiring some hardware and establishing communication with the processor. I have a machine related project coming up. So if you would like, I could give some tips and share past experiences. Keep in touch… and thank you.

4 Likes
#41

Are any of those PLCs Siemens with SCADA?

I have a couple of PCs I decommissioned between 2005-2010, so they probably have a viable version of the Stuxnet Virus onboard.

This, from Wiki: Stuxnet is a malicious computer worm, first uncovered in 2010, thought to have been in development since at least 2005. Stuxnet targets SCADA systems and is believed to be responsible for causing substantial damage to Iran’s nuclear program. Although neither country has openly admitted responsibility, the worm is widely understood to be a jointly built American/Israeli cyberweapon.

Anyone out there have an IR-1 or IR-2 centrifuge sim? I think it would be cool to recreate what happened.