Author Topic: Geting started with PLCs  (Read 5620 times)

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Offline Emil

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Geting started with PLCs
« on: September 29, 2020, 01:53:59 pm »
I'm planning to get a PLC to learn the basics of PLCs and ladder logic. I don't have a specific project that needs a PLC right now, but I would like to learn enough to know when a PLC is the right choise and to hit the ground running if I need one for a simple project.

There are some low cost PLCs on AliExpress, but if they specify what software is required, it's Mitsubishi or Siemens software which appares to be very expensive.

Are there any brands of PLCs that have free software for programming and simulation?

Any suggestions for brands to use or avoid?
 

Offline Doctorandus_P

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Re: Geting started with PLCs
« Reply #1 on: September 29, 2020, 04:31:06 pm »
If you buy one (or a few) of those FX1N or FX2N PLC boards from Ali for around EUR20 to EUR30, then you'll probably find they're compatible with the software from one of those manufacturers you mentioned.

I bought one of these just out of curiousity, even though I abhor ladder diagrams and have no interest in PLC software myself.
I bought it because:

* Curiousity.
* STM32F103 CPU.
* Hardened I/O.
* Solid power supply section (Common mode filtering, SMPS, big Elco's)

You can choose between lots of versions Points to watch out for are:
* Number of I/O.
* Relay or Transistor outputs.
* PCB or DIN rail mountable.
* Connector quality. I prefer the green detachable connectors.

My version even got the STM32 programming pins broken out on some solder pads.
The only real disadvantage I've discovered on my PCB is that the RS485 driver is an SN75176 with no external extra protection. This is a very old and not very robust RS485 driver chip. But if needed, a SOIC-8 is not that hard to replace either.
« Last Edit: September 29, 2020, 04:35:23 pm by Doctorandus_P »
 

Offline Emil

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Re: Geting started with PLCs
« Reply #2 on: September 29, 2020, 09:11:08 pm »
If you buy one (or a few) of those FX1N or FX2N PLC boards from Ali for around EUR20 to EUR30, then you'll probably find they're compatible with the software from one of those manufacturers you mentioned.

I'm trying to avoid the software from those manufacturers since I heard that the prices are in the four digit range. But I'v not actually been able to find a price on their websites so that may be incorrect/outdated.
 

Online H.O

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Re: Geting started with PLCs
« Reply #3 on: October 01, 2020, 10:14:59 am »
Several years ago I bought one of those FX1N/2N something PLC "clones" from AliExpress. It came with a CD containing the official Mitsubishi software, I think it was IEC developer but I'm not sure (they've had a few development tools over the years). Most likely NOT legit but that's what happened in my case.

I was surprised to find that the "clone" had sinking output and sourcing inputs which is not quite what we're used to here in Europe but it's apparently more of the norm in places like Japan. The orignial FX1N/2N that I've used have had sourcing outputs and sinking inputs but it's quite possible the original exists in both configurations.

Anyway, I ordered it mostly out of curiosity, played around with for a bit and it seemed to work just fine - apart from the "inverted" I/O.

You could take a look at one of the smaller units like Schneider Zelio, Siemens Logo, Crouzet Millenium etc.

EDIT: Or you could look at Codesys. Get some EtherCAT or MODBUS I/O modules and run it on a RaspberryPi. Not something I'm personally experienced with but I've meaning to try it - one day.
« Last Edit: October 01, 2020, 10:18:16 am by H.O »
 

Offline elekorsi

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Re: Geting started with PLCs
« Reply #4 on: October 13, 2020, 09:52:41 am »
I would suggest to try Unitronics. They have great PLCs for small and mid projects. The software is completely FREE, downloadable from their site.
I would suggest an all in one PLC+HMI, something like Samba series, or Vision.

If you want to learn, stay away from LOGO, Zelio logic, etc. They are not PLCs, but smart relays. Ladder is awful there...


In Europe i think that Siemens PLCs are still the most common, especially on bigger automation systems and process systems. In US, of course the Allen Bradly.
For a self learning beginner i would recomend to stay away from Siemens Simatic due to its complexity and price. I am familliar with TIA portal quite well, was even programming some years ago
Now i use it mostly for maintenance purposes and maybe sometimes for some simple changes. For everything else i leave it to a programmer who do this every day and know exactly what he is doing...

 

Offline Galenbo

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Re: Geting started with PLCs
« Reply #5 on: October 14, 2020, 06:51:09 am »
I am a PLC professional, at the moment mainly Siemens and Rockwell.
Even now, I strongly advise against Siemens for everybody who has the choice.

Before, I had some pretty good experiences with Wago. They have starter kits with the license included, and their coupler extensions can be piloted with other systems too.
They are also compatible with Codesys, but I didn't try that at that moment.
If you try and take a cat apart to see how it works, the first thing you have on your hands is a nonworking cat.
 

Offline shooter

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Re: Geting started with PLCs
« Reply #6 on: October 27, 2020, 08:51:12 am »
have a look at codesys software, it is free.
The WAGO plc works with it, and you can start with just a controller and make it as big as you want.
 

Offline Doctorandus_P

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Re: Geting started with PLCs
« Reply #7 on: October 29, 2020, 11:50:21 am »
If you have some Linux compatible hardware, it might be worth looking into LinuxCNC.
It's main function is to use Linux as a controller in a CNC machine and generate movements for the motors, but part of it is a soft-plc for auxiliary functions.
 

Offline effgee

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Re: Geting started with PLCs
« Reply #8 on: December 14, 2020, 10:01:58 pm »
Automation direct 'Do-more' software is free and includes simulation.
I've found it very easy to use, plenty of free training videos but it's mostly intuitive.
 

Offline effgee

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Re: Geting started with PLCs
« Reply #9 on: December 14, 2020, 10:08:34 pm »
 

Offline WattsThat

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Re: Geting started with PLCs
« Reply #10 on: December 14, 2020, 11:05:21 pm »
When money is no object, Rockwell in the USA and Siemens elsewhere in the world may dominate the PLC market space but...

Automation Direct is by far the most cost effective hardware and software on the planet, period.

Unitronics hardware and software is very nice and cost effective. If you need a color touch screen, they’re easy to use and one of the few if not only ones that directly support the Rockwell CIP Ethernet protocol.

IMO, Codesys has a learning wall, not a learning curve. It is absolutely the worse choice for non-experienced PLC programmers. I’ve used it for several hardware platforms, I absolutely despise the environment. While it is said that it does everything, it does nothing well. It’s painful at best as is typical for any tool that tries to be all things to all people.
 

Online rstofer

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Re: Geting started with PLCs
« Reply #11 on: December 21, 2020, 06:41:10 pm »
Again, AutomationDirect has PLCs with free software.  I didn't shop prices
https://www.automationdirect.com/adc/overview/catalog/programmable_controllers

These are not what I would consider "mainstream" PLCs and I would have a tendency to want to use Fanuc devices since that is what I am familiar with.  I don't think the software is free.

There are some DIY PLCs - Google for them

In the end, it comes down to ladder logic and the most important thing to learn is how to code finite state machines in ladder logic for a particular controller.  It's a lot easier to do with a PLC than it was with relays.  Fifty years ago, we use stepping switches - worked well.

https://en.wikipedia.org/wiki/Stepping_switch



 

Offline VRomanov

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Re: Geting started with PLCs
« Reply #12 on: February 08, 2021, 11:06:17 pm »
I'm a PLC programmer by career. I always recommend first-timers to purchase a MicroLogix 1100 series from Rockwell Automation. The software for that specific model is free and is something is widely used in the industry.

Others have recommended a number of PLCs and platforms that are also acceptable, but I personally have not seen many of them in the field (in North American plants).

If you need a guide on how to get the software, including an emulator of the PLC, if you don't want to spend any $, here's one: https://www.solisplc.com/tutorials/downloading-a-free-copy-of-rslogix-500-rslogix-500-emulate-rslinx

Also, you can get a MicroLogix 1100 on eBay for 150-200$ USD.

All the best and feel free to reach out if you have questions,
Vlad
 

Offline WattsThat

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Re: Geting started with PLCs
« Reply #13 on: February 09, 2021, 03:37:06 am »
Rockwell is only used by those spending other people’s money.

It can be a full time job getting their stuff to work due to their use of the Apple model of forced version control. I work with Studio 5000 and their very overpriced hardware only because I’m forced to.

With Automation Direct, for $200, you get the hardware, software and tech support. There is a reason they own the low cost plc market.

To each their own. Choose carefully. Especially when spending your own money.
 

Offline Dimitris

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Re: Geting started with PLCs
« Reply #14 on: February 12, 2021, 08:04:25 am »
I've used Zelio PLC from Schneider Electric in a couple of projects and I was very pleased with their programming software.
Units like this one

https://www.se.com/ww/en/product/SR2B121BD/compact-smart-relay-zelio-logic---12-i-o---24-v-dc---clock---display/
http://www.jel.gr
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Offline spudboy488

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Re: Geting started with PLCs
« Reply #15 on: February 12, 2021, 03:12:13 pm »
I'm going through the same thing in I'm trying to learn a bit about ladder programming and PLCs in general.

I have been using the simulator in the Automation Direct Do-more Designer software to get the basics before buying any hardware.

I have not purchased this yet, but the Click series of PLCs from Automation Direct are cheap and the software is free. It's different from Do-more, I have come to find out. Their "CLICK Basic PLC, 24 VDC required, serial ports, Discrete Input: 8-point, DC, Discrete Output: 6-point, sinking" costs only $69 USD.

Check here: https://www.automationdirect.com/adc/shopping/catalog/programmable_controllers/click_series_plcs_(stackable_micro_brick)/plc_units
 

Offline Galenbo

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Re: Geting started with PLCs
« Reply #16 on: February 16, 2021, 04:58:57 pm »
I see some series they sell:

Productivity Series Controllers
Do-more Series (BRX, H2, T1H) PLCs (Micro Modular & Stackable)
DirectLogic Series PLCs (Micro to Small, Brick & Modular)
CLICK Series PLCs (Stackable Micro Brick)

Instead of loosing some days in the specs, I ask here:
Are they somewhat related, or just a collection of worldwide rebrands?
What are the major spec differences ?
If you try and take a cat apart to see how it works, the first thing you have on your hands is a nonworking cat.
 

Online Ground_Loop

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Re: Geting started with PLCs
« Reply #17 on: February 18, 2021, 12:44:20 am »
I've been designing and programming large industrial PLC systems for over 30 years. If you are getting into this as a career starter you need to find a way to get your hands on the main line brands Allen-Bradley, Siemens, Mitsubishi, Schneider. Ladder logic, structured text and function block programming are only a small part of the over all system. Choosing and setting up the IO and communication links is nearly as time consuming and specific to the brand. 

For fun, Automation Direct is an option, but don't tell an interviewer that is the extent of your experience.
There's no point getting old if you don't have stories.
 

Offline WattsThat

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Re: Geting started with PLCs
« Reply #18 on: February 18, 2021, 03:17:42 am »
Quote
For fun, Automation Direct is an option, but don't tell an interviewer that is the extent of your experience.

Everybody’s got to start somewhere and most importantly, it depends upon who’s doing the interviewing. Yeah, I agree if it’s a Rockwell shop, good luck, but that’s only what, 50% of the US market?  ;)

The Automation Direct Click and DirectLogic product lines are rebranded Koyo out of Japan. Not sure about the other product lines, no experience with those.
 

Offline wizard69

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Re: Geting started with PLCs
« Reply #19 on: March 24, 2021, 07:33:00 pm »
The Automation Direct stuff is pretty good in my opinion!   The A&B stuff has become a bit of a nightmare to maintain.

I've been designing and programming large industrial PLC systems for over 30 years. If you are getting into this as a career starter you need to find a way to get your hands on the main line brands Allen-Bradley, Siemens, Mitsubishi, Schneider. Ladder logic, structured text and function block programming are only a small part of the over all system. Choosing and setting up the IO and communication links is nearly as time consuming and specific to the brand. 

For fun, Automation Direct is an option, but don't tell an interviewer that is the extent of your experience.
 

Offline BeBuLamar

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Re: Geting started with PLCs
« Reply #20 on: May 10, 2021, 03:22:11 pm »
I use all different brands of PLC but found automation direct is best if money is of concern. I strong recommend the productivity series. For lower cost the Click. The DirectLogic are too old now.
 

Offline Robert Smith Eco Warrior

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Re: Geting started with PLCs
« Reply #21 on: May 10, 2021, 03:26:35 pm »
I have a Mitsubishi PLC somewhere. Quite a big complex thing with many inputs and outputs. I couldn't get to grips with the software so it has been shelved somewhere.
I should dig it out and decide what to do with it.
 

Offline V_King

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Re: Geting started with PLCs
« Reply #22 on: May 12, 2021, 02:57:04 pm »
Because I am coming from using high level programming languages for the projects, when I started looking into PLCs a few years back for a simple automation project for a building, all the PLC ladder logic made me cringe!

If you are looking going into automation industry, then you need to go with the big buy brands. If all is for personal projects I would suggest looking into arduino based PLCs. Yes, there are a few options of those. Nice simple programming, yet all the interfacing on the hardware level is sorted, like on PLCs.

Another option I found very interesting is Sigmatek in Austria. They are using object oriented programming with their PLCs, everything is Industry 4.0 with ton of connectivity and development software is free. The options list is comprehensive and everything is very well designed. The only issue is finding a distributor, whom is happy to sell to makers. They are a bit of a boutique manufacturer.

The last option would be Siemens LOGO devices. They are for basic tasks, plenty of cheap ones on second hand market, and you can get the software cheap or for free (I think Linux version is free, win version CD is like £20-40).
« Last Edit: May 12, 2021, 02:58:54 pm by V_King »
 

Offline BeBuLamar

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Re: Geting started with PLCs
« Reply #23 on: May 12, 2021, 03:57:45 pm »
My favorite PLC programming language is one that most people hate namely the Statement List like the Siemens Step 5 and Step 7. The ladder is OK. High level language is good but you can make the PLC running an endless loop.
For a simple project I would use the Automation Direct Click series. They are cheap and the programming software is free. Nowaday, I use their Productivity 2000 series for most of my projects.
 

Offline janoc

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Re: Geting started with PLCs
« Reply #24 on: May 12, 2021, 04:21:58 pm »
I had to get into PLCs for an industrial project a few years ago - ABB AC500-eCo series is pretty cheap (the basic CPU + some I/O costs about 400 euro or so), the software is a free download (Codesys + ABB Automation Builder).

But keep in mind that Codesys alone isn't sufficient, typically the PLC needs to be configured first. Unlike with microcontrollers where your firmware is setting up I/O and configuring peripherals, with PLCs it is usually done using some proprietary vendor software and (sometimes) proprietary cables.

With the ABB PLCs this is not an issue as the ABB sw is a free download and the PLC uses either a normal serial (RS232) cable or USB for connection. But then the hw is likely more expensive than the cheap Chinese PLCs.
 


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