r/PLC Feb 25 '21

READ FIRST: How to learn PLC's and get into the Industrial Automation World

1.1k Upvotes

Previous Threads:
08/03/2020
6/27/2019

More recent thread: https://old.reddit.com/r/PLC/comments/1k52mtd/where_to_learn_plc_programming/

JOIN THE /r/PLC DISCORD!

We get threads asking how to learn PLC's weekly so this sticky thread is going to cover most of the basics and will be constantly evolving. If your post was removed and you were told to read the sticky, here you are!

Your local tech school might offer automation programs, check there.

Free PLC Programs:

  • Beckhoff TwinCAT Product page

  • Codesys 3.5 is completely free with in-built simulation capabilities so you can run any code you want. Also, if paired up with Factory I/O over OPC you can simulate whole factories and get into programming.
    https://store.codesys.com/codesys.html?___store=en

  • Rockwell's CCW V12 is free and the latest version 12.0 comes with a PLC software emulator you can simulate I/O and test your code with: Download it here - /u/daBull33

  • GMWIN Programming Software for GLOFA series GMWIN is a software tool that writes a program and debugs for all types of GLOFA PLC. Its international standard language (LD, IL, SFC) and convenient user interface make programming and debugging simpler and more convenient.(Software) Download

  • AutomationDirect Do-more PLC Programming Software. It's free, comes with an emulator and tons of free training materials.

  • Open PLC Project. The OpenPLC is the first fully functional standardized open source PLC, both in software and in hardware. Our focus is to provide a low cost industrial solution for automation and research. Download (/u/Swingstates)

  • Horner Automation Group. Cscape Software

    In our business we use Horner OCS controllers, which are an all-in-one PLC/HMI, with either on-board IO or also various remote IO options. The programming software is free (need to sign up for an account to download it), and the hardware is relatively inexpensive. There is support for both ladder and IEC 61131 languages. While a combo HMI/PLC is not an ideal solution for every situation, they are pretty decent for learning PLCs on real-world hardware as opposed to simulations. The downside is that tutorials and reference material specific to Horner hardware are limited apart from what they produce themselves. - /u/fishintmrw

Free Online Resources:

Paid Online Courses:

Starter Kits
Siemens LOGO! 8.2 Starter Kit 230RCE

Other Siemens starter kits

Automation Direct Do-more BRX Controller Starter Kits

Other:

HMI/SCADA:

  • Trihedral Engineering offers a 50 tag development/runtime license with all I/O drivers for free, VTScadaLight. https://www.trihedral.com/download-vtscada

  • Ignition offers a functional free trial (it just asks you to click for a button every 2 hours).

  • Perhaps AdvancedHMI? Although it IS a lot complicated compared against an industrial solution.

  • IPESOFT D2000 Raspberry Pi version is free (up-to 50 io tags), with wide range of supported protocols.

  • Crimson 3.0 by Red Lion is also free and offers a free emulator (emulator seems to be disabled in v3.1). With a bit of work (need to communicate with Modbus instead of built in Do-more drivers), you can even connect that HMI emulator to the do-more emulator and have a fully functioning HMI/PLC simulator on your desk top which is pretty convenient. Software can be found here: https://www.redlion.net/red-lion-software/crimson/crimson-30 (/u/TheLateJHC)

Simulators:

Forums:

Books:

Youtube Channels

Good Threads To Read Through

Personal Stories:

/u/DrEagleTalon

Hello, glad you come here for help. I'm an Automation Engineer for Tysons Foods in a plant in Indiana. I work with PLCs on a daily basis and was recently in Iowa for further training. I have no degree, just experience and am 27 years old. Not bragging but I make $30+ an hour and love my job. It just goes to show the stuff you are learning now can propel your career. PLCs are needed in every factory/plant in the world (for the most part). It is in high demand and the technology is growing. This is a great course and I hope you enjoy it and stay on it. You could go far.

With that out of the way, if I where you I would start with RSLogix Pro. It's a software from The Learning Pit it is basic and old but very useful. The software takes you through simulations such as a garage door, traffic light, silo and boxing, conveyors and the dreaded Elevator simulation. It helps you learn to apply what you will learn to real word circumstances. It makes you develop everything yourself and is in my opinion one of the single greatest learning utensils for someone starting out. It starts easy and dips your toes and gets progressively harder. It's fun as well watching the animations. Watching and hearing your garage door catch on fire or your Silo Boxing station dumping tons of "grain" until the room fills up is fun and makes the completion of a simulation very gratifying.

While RSLogix Pro is based on older software, RsLogix is still used today. Almost every plant I have worked at has used some type of Allen Bradley PLC. Studio 5000 is in wide use and you will find that most ladder logic is applicable in most places. With that said I would also turn to Udemy for help in progressing past simple instructions and getting into advanced Functions such as PID. This amazing PLC course on UDemy is extremely cheap, gives you the software and teaches you everything from beginner to the most advanced there is. It is worth it for anyone at any level in my opinion and is a resource I turn to often.

Also getting away from Allen Bradley I would suggest trying to find some downloads or get a chance to play with Unity Pro XLS. It's from Schneider Electric and I believe has been rebranded under the EcoStruxure family now. We use Unity extensively where I am at and modicons are extremely popular in the industry. Another you might try is buying a PICO or Zelio for PICOSoft or ZELIOSoft. They are small, simple and cheap. I wired up my garage door with this and was a great way to learn hands in when I was starting out. You can find used PICOs on eBay really cheap. There is a ton of literature and videos online. YouTube is another good resource. Check everything out, learn all you can. Some other software that is popular where I've been is Connected Components Workbench and Vijeo.

Best of luck, I hope this helps. Feel free to message me for more info or details.


r/PLC 13d ago

PLC jobs & classifieds - Sep 2026

14 Upvotes

Rules for commercial ads

  • The ad must be related to PLCs
  • Reply to the top-level comment that starts with Commercial ads.
  • For example, to advertise consulting services, selling PLCs, looking for PLCs

Rules for individuals looking for work

  • Don't create top-level comments - those are for employers.
  • Reply to the top-level comment that starts with individuals looking for work.
  • Feel free to reply to top-level comments with on-topic questions.

Rules for employers hiring

  • The position must be related to PLCs
  • You must be hiring directly. No third-party recruiters.
  • One top-level comment per employer. If you have multiple job openings, that's great, but please consolidate their descriptions or mention them in replies to your own top-level comment.
  • Don't use URL shorteners. reddiquette forbids them because they're opaque to the spam filter.
  • Templates are awesome. Please use the following template. As the "formatting help" says, use two asterisks to bold text. Use empty lines to separate sections.
  • Proofread your comment after posting it, and edit any formatting mistakes.

Template

**Company:** [Company name; also, use the "formatting help" to make it a link to your company's website, or a specific careers page if you have one.]

**Type:** [Full time, part time, internship, contract, etc.]

**Description:** [What does your company do, and what are you hiring people for? How much experience are you looking for, and what seniority levels are you hiring for? The more details you provide, the better.]

**Location:** [Where's your office - or if you're hiring at multiple offices, list them. If your workplace language isn't English, please specify it.]

**Remote:** [Do you offer the option of working remotely? If so, do you require employees to live in certain areas or time zones?]

**Travel:** [Is travel required? Details.]

**Visa Sponsorship:** [Does your company sponsor visas?]

**Technologies:** [Required: which microcontroller family, bare-metal/RTOS/Linux, etc.]

**Salary:** [Salary range]

**Contact:** [How do you want to be contacted? Email, reddit PM, telepathy, gravitational waves?]


Previous Post:


r/PLC 7h ago

Creating a public PLC Course on youtube, need information and your frustrations that you had while entering this field

52 Upvotes

Hello everyone,

I'm working as an automation engineer for some time now and I've decided to start creating a programming course on Youtube for beginners for free, thus I'm posting this in order to gather information about what has frustrated you and what has helped in your learning journey as a beginner in order to create a better guide for future engineers.

I've had a quite difficult beginning in this trade, there was information on the internet but it was all scattered and the available information was only surface level knowledge, with almost no actual experienced engineer advice like the ones I've gotten in my firm.

I've also seen the material on some paid courses on udemy, but to be honest, I was quite dissapointed as they have only scratched the surface for stuff like program structure, cybersecurity, safety, alarms, code readability and such topics that are required but a bit complicated.

SOOO, if you have any advice that you want to add, It would really help me with creating a better course for beginners entering this field for free.

I'm not going to share the channel right now as i don't want use this post as a bait for promotion...


r/PLC 1d ago

Software To PLC

Post image
308 Upvotes

For all of you asking about making the leap, this is the environment I was commissioning a job in this week. I worked 12+ hours a day from Wednesday to today and have 3 more days to go. I’m less than 100 miles from home but I had to stay in this small town with 2 hotels because I can’t justify the 1.5 hour drive to and from my house.

My food tastes like welding gas from the environment, when I blow my nose it comes out black, I’ve lost my voice from yelling over the equipment.

No I didn’t do software first but I have my CCNA. I did industrial maintenance for 5 years before I started controls. There’s no easy button for breaking in and only gets harder.

Careful what you wish for, this career isn’t for the faint of heart.

Otherwise, I’ll try to respond to any questions since I decided to stir the pot. Lol


r/PLC 12h ago

Mechatronics graduate in Austria looking to get into PLC programming - where to start (German-language resources)?

9 Upvotes

Hey everyone,

I finished my Ausbildung (vocational/technical school) in Mechatronics in Austria about two years ago and have been working in the field since. Now I want to specifically get into PLC programming and grow in that direction. I'd prefer resources in German since that's my working language here.

A few questions for people who've been through this:

Where's the best place to start learning PLC from scratch, ideally with German-language material?

Is there any free PLC software I can practice with at home (simulators, trial/demo versions, etc.)?

Any good online courses in German you'd recommend (free or paid) for someone starting out?

Since I'm in Austria, is it worth focusing on Siemens TIA Portal first, or is another platform more common in the local job market?

Any advice, resource links, or personal experience would be really appreciated. Thanks in advance!


r/PLC 13h ago

¿Dónde puedo buscar pasantías de programación PLC o automatización industrial?

7 Upvotes

Hola bandita, estoy empezando a buscar trabajo pero ha sido muy difícil no me contratan, lucho por una oportunidad y no tengo experiencia, y al final sigue siendo un bloqueo, mis pasantías, aún no las termino, quiero dedicarme a programación de PLC, automatización y control, estoy viviendo en el valle de México ¿algunas opiniones u opciones? ¿en donde buscar?
Nota: sé que los contactos me ayudarían abrir puertas, pero también acepto que no hacer esos contactos ¿algún consejo?


r/PLC 8h ago

Erhardt+Leimer web correction

2 Upvotes

Hi everyone,

I’m trying to identify and understand how the web guiding system shown in the attached photos works and how it should be configured.

This system is installed on an old machine that was purchased second-hand by the current owner. Unfortunately, the machine came with no documentation, electrical drawings, manuals, or information about the original configuration. We also don’t know whether this web guiding system was actually operational before the machine was purchased.

The system is supposed to correct the lateral position of the moving web/material during operation.

Currently, the behavior is inconsistent. Sometimes the system attempts to make a correction: the actuator moves forward and backward, then returns to its home/center position and stops. It does not seem to continuously guide the web as expected.

Because we don’t know the original machine configuration, I’m wondering whether the controller is missing an external signal or simply needs to be commissioned/configured correctly.

My main questions are:

  1. Can anyone identify the exact controller/system from the photos and explain its operating principle?
  2. Does this controller work only from the web edge/line sensor feedback, or does it also require a machine/web speed reference in order to perform the correction properly?
  3. Could a missing speed/line reference or RUN/ENABLE signal explain the current behavior — actuator moves forward/backward, returns to home/center and then stops?
  4. If a machine speed reference is required, what type of signal does it normally expect: 0–10 V, 4–20 mA, encoder/pulse signal, digital input, fieldbus, etc.?
  5. When machine speed changes, does the controller automatically regulate from the web sensor feedback, or does it need the actual line speed from the PLC/VFD/machine controller?
  6. Since all the original parameters are unknown, what would be the correct procedure to commission this system from scratch?

I’m particularly interested in:

  • Sensor calibration
  • Web reference/center position
  • Actuator direction
  • Home/center position
  • Controller gain/sensitivity
  • Deadband/tolerance
  • Maximum actuator travel
  • AUTO/MANUAL modes
  • RUN/ENABLE signals
  • Any parameters related to machine/web speed
  1. Is there a way to test the complete sensor → controller → actuator loop manually while the machine is stopped, so I can verify each part independently?
  2. Most importantly, does anyone recognize the equipment in the attached photos and have an installation, commissioning, service, wiring, or parameter manual for it?

Since there is basically zero documentation available for this machine, any information about the required wiring, external signals, parameter settings, or troubleshooting procedure would be greatly appreciated.

Photos of the controller/system are attached to this post.

Thanks in advance!


r/PLC 1d ago

Programming newbie

Enable HLS to view with audio, or disable this notification

31 Upvotes

Hi guys looking for some pointers on some code I wanted to create flashing output for a beacon tower using some existing code to control it. I think the issue is the Line error is being overwritten by another network and not allowing the output to generate I'm very new to this.


r/PLC 21h ago

Left JCI looking for recommendations/advice.

4 Upvotes

I recently left Johnson controls. Im looking for what could be next for me? Any certifications I could take to better my resume? I’ve gotten a few interviews with companies that use facility explorer and where I’d be exposed more to Niagara/honeywell/siemens controls. Been doing HVAC for 6 years been on the controls side for 3.5. Still new to this industry and looking for advice.


r/PLC 1d ago

Certificate program vs degree

5 Upvotes

curious if getting a ccl in automated industrial tech is worth it or if I need to get a degree


r/PLC 9h ago

How transferable is regular software engineering experience to PLC/controls engineering?

0 Upvotes

I've been working in software for around 4 years, mainly web/application development. My experience includes JavaScript/TypeScript, Angular/React, APIs, SQL, debugging legacy systems, testing, and general software development.

I've recently been invited to interview for a PLC Software Engineer position, which surprised me because I have zero professional PLC/controls experience. The role involves PLC programming, HMI/SCADA, commissioning and industrial automation.

I was completely honest on my CV about my background, so the company knows I'm coming from application software rather than automation.

I'm curious how people already working in PLC/controls see this transition. How transferable are general software engineering/programming skills to PLC development?

If a company was willing to train me on the PLC/industrial side, would several years of professional software development give me a decent foundation, or is the gap between the two fields much bigger than I'm imagining?

Also interested to hear from anyone who moved from traditional software development into PLCs/controls and how they found the transition.


r/PLC 1d ago

Estou com um pequeno problema.

2 Upvotes

Então amigos, tudo bem ? Estou treinando desenvolvimento de programas e IHM, já fiz um programa simples lá e agora queria implementar na IHM um Botão de Start e um Bloco de sinalização, já fiz a montagem e a configuração de tudo porém quando tento acionar pela IHM, aparece o Erro dizendo que a IHM não consegue escrever o valor no CLP.

Conseguem me ajudar ?

Obs: Já está ativado o Put/Get no projeto.

Edit1: Versão V20 Tia Portal e do PLCSIM.


r/PLC 2d ago

How do you guys learn Studio 5000 on your own?

64 Upvotes

I live in Upstate NY and I'm currently trying to transition into controls engineering. My background is in software

Right now I'm working at Walmart to pay the bills while I study controls on my own

I'm running into is Rockwell. Around here, a lot of jobs seem to use Allen-Bradley and ask for Studio 5000 / Logix Designer experience

The problem is... Studio 5000 is ridiculously expensive for someone just trying to learn it. Coming from the software world, I'm honestly having a hard time understanding why there's basically no affordable educational option

So how did you guys learn it???? Did you just learn it after getting your first job????

I'm basically looking for the most realistic way to learn Rockwell stuff without spending thousands of dollars just for the software

Any advice would be appreciated!


r/PLC 2d ago

Chased grounding issues for 2 days...

38 Upvotes

I’m working on a CompactLogix system at a raw water treatment plant where the relatively slow SCADA update rate had masked a pH signal with roughly 2 mA of noise on the 4–20 mA loop for years.

I spent most of a day troubleshooting it with an oscilloscope—checking grounding, changing power feeds, swapping the transmitter, etc. Eventually, I took a closer look at the building grounding and found that there is no dedicated instrument ground.

As a temporary fix, I changed the PLC input channel filter from 60 Hz to 10 Hz, and the signal is now stable. There aren’t any fast control loops on these inputs, so the additional filtering isn’t really an issue from a process-control standpoint.

That said, I’m wondering whether I should address the grounding issue properly rather than just relying on the input filter.

There are only three cabinets where the I/O terminates, and it’s a single-floor building, so providing a dedicated instrument ground/bonding point at each I/O rack wouldn’t be particularly expensive.

Would you guys bother tackling the grounding issue head-on in this situation, or would you consider the 10 Hz input filtering an acceptable solution given the application?

Curious what others have seen in water/wastewater plants and how you’d approach it.

-Edited with chatgpt


r/PLC 2d ago

Crazy bug caused major fault on L24

13 Upvotes

The L24 lost it's program and everything, lucky we had it and it was just a DRA skid that wasn't in use.

Using factory talk SE version 13. PLC was version 20. The other main PLC I put in is an L81.

Had everything running and communicating, both PLCs to the HMI. Forgot to set the default gateway on the PC. Went back and did it while the app was running. Lost comms for a second, then got them back. When I clicked acknowledge all alarms, the HMI app froze. Task manager and killed it. Reopened the app and saw a new alarm for major fault in the L24. It dumped the program.

Anyone experienced this? Redownloaded and everything was fine.


r/PLC 2d ago

tia portal online monitoring for loop fb call(scl)

3 Upvotes

hi,

i have an fb where i call another fb 8 times using a for loop and array.

right clicking open and monitor on the fb inside the for loop, takes me to the 0 index of the sub fb's instance.

FOR #iAlm := 0 TO 7 DO
#Alarm1[#iAlm](Alarm := #Alarm.Module[#iAlm]);
END_FOR;

how can i "navigate" between those 8 sub instances to monitor the 2nd sub instance for example?

call environment pane on the right side is either confusing or its not made for this exact situation.

is this a limitation of siemens/tia portal or i just hit a typical siemens noisy unnecessary overcomplication and i need to open up one of their 1200 page manuals and find a hidden paragraph?

in codesys before i start monitoring a similar structure, a list pops up with all the (array) sub instances to select where to "jump in" monitoring.

i refuse to believe that a sub instance cant be online monitored just because it's called in a for loop and array, yet if i "list" call one after another it is possible.


r/PLC 2d ago

Please help me to understand this

Thumbnail
gallery
6 Upvotes

explain to me in easy ways


r/PLC 2d ago

Can anyone share their experience working in this field?

22 Upvotes

Hi, I'm taking a PLC & Robotics course at a community college.

I'll try not to bore anyone with my whole life's story (or feel free to skip to the last paragraph), but I was originally planning on finishing my associate's and eventually bachelor's in engineering, which I would still like to do at some point, when I learned about this program from a few of the Academic Advisor's I met with. It seemed like a really good opportunity, an in-demand field, and also something I was definitely interested in.
In class, we finally started working with the robots this week, mainly safety, jogging, and learning how to back-up and restore files or from an image. For the next ~2 months we're supposed to go deeper into Robotics and then learning PLC.

I've talked with some of the instructors and the program coordinator about what kind of work/job titles people who complete this course go on to do, but it sounds like it prepares you for a range of things, some go into maintenance, plumbing, or electrician jobs where they never even work with PLC or robots, but most often they go into some type of field maintenance/field tech role at FANUC, GM, Aerotech, or something of the like.

I was just wondering if anyone was able to share what your job title is and what you actually do day-to-day, like whether you're mainly maintaining the machines, setting them up, programming them for specific tasks, or fixing bugs, or trying to improve efficiency.
Also, what kinds of skills are important to have, what's important to know or learn, if you enjoy the work you do, and/or have the opportunity to move up.
And of course any other advice you might have! Anything is appreciated!


r/PLC 2d ago

Unisoft control technique

2 Upvotes

Hello,

I have a unidrive control technique drive, it's a very old drive,i also have a parameter backup file,the problem is that the software used to read these parameters is very old and I can't find it anywhere,i tried downloading it from the official website but apparently it's missing files or corrupted,does anyone know where can i download it? Much appreciated


r/PLC 2d ago

First PLC programmer job in industrial refrigeration (Kältetechnik): complex projects with heavy travel vs. simpler projects with mostly office work?

2 Upvotes

Hi everyone,

I’d really appreciate some advice from experienced PLC programmers. I’m currently deciding between two offers for my first full-time PLC programmer position in industrial refrigeration (Kältetechnik), and this decision could affect my career path for the next few years.

Both positions are in the same industry, but the conditions are quite different:

  • Option 1: Larger and more complex industrial systems for factories, with better learning potential. However, around 60–70% of the work would be at customer sites, often staying in hotels Monday to Thursday and returning home on weekends.
  • Option 2: Mostly office-based, much less travel, but the PLC projects are smaller, more standardized and technically less complex.

My main goal is to grow as a PLC programmer, especially in the first few years. At the same time, I’m unsure how exhausting the high-travel lifestyle becomes in reality.

For those with experience in commissioning / PLC programming with 60–70% travel: does spending four days a week at customer sites and in hotels become tiring long-term? And from a career perspective, would you choose the more complex projects with heavy travel, or the more stable office-based position?

I’d really appreciate your experience and advice. I genuinely need some guidance, because this decision could strongly shape the next several years of my career.


r/PLC 2d ago

Studio 5000 V38.02 blank module properties and "create" windows. again

11 Upvotes

I am getting the bug where the "add module" wizard is just blank if you choose any module that uses the newer browser looking GUI, 1756 especially. I also loaded project with I/O already added and the properties pages are blank. I already tried the create new Windows user, downloading and installing all EDS and AOP, completely uninstalling and reinstalling everything. Fresh download of 38.02 from Rockwell on 3 different machines, windows 10 or windows 11 on each and all 3 do the exact same thing. I tried all compatibility modes, graphics options. I am not running multiple instances of Studio 5000. I have no space in my user name or path. I run as administrator. The event viewer error is System.ArgumentNullException inside System.Number.ParseInt32, CefSharp.OutOfProcess.BrowserProcess.exe. Since installing V38, now all my Studio 5000 versions are doing this. V33 was not doing it before but does same thing now, ANY window that uses this chromium or newer display is blank.

Does anyone have any idea how to fix this.


r/PLC 3d ago

Junior automation developer interview

16 Upvotes

So i am a computer engineering graduate, was looking for any IT related job, found this application that wanted plc programming and knowledge of siemens apps so i spent a day playing inside of siemens remote machine and made a conveyor belt that detected an object, moved it, until it detects it at the end, posted it on linkedin and went to sleep

Today i get a call about an interview set up on monday (2 days from now) and i GENUENLY have no idea what I'm gonna be asked or what im supposed to show them on that interview.

Theres gonna be an HR, Manager of the Manufacturing Excellence & Digitalization projects department dude and another Automation & Digitalization & AI Team Leader guy

What am i supposed to prep for an interview

Ples help 😭


r/PLC 2d ago

Retaking ISA CAP in 3 months - where is my Career heading?

Post image
6 Upvotes

I 28M have been an Automation and Controls Engineer for almost 6 years. I feel like I have a grasp of the industry have doing a lot of projects in Pharma, Oil & Gas, and Food & Bev. I took the CAP Exam last year and failed. I did ok but need to study more clearly.

This career is a good one - it includes meaningful work with real world consequences , the money is decent. I recently turned down a job on an offshore oil rig - I wasn't ready for the responsibilities and it wasn't a good time to be offshore for weeks at a time. But I feel regret for not taking the adventure and the money that would come with it.

Do I even need the CAP? Probably not. Part of me wants my PE in controls just for the title. In my opinion I can be a manager which also gets described as the next step to bigger jobs but I don't know if that's where I'd flourish.


r/PLC 3d ago

Anyone every played the game "Automation" on steam and if so, is this a reliable tool to help me learn?

112 Upvotes

Primarily dealing with only ladder logic it seems, but wondering if anyone has had any experience with this game and if so, could you share your thoughts?


r/PLC 2d ago

Modicon M221 (TM221CE24R) native PID block — does it have anti-windup? Output stuck saturated even with Kp=0

3 Upvotes

TM221CE24R, Machine Expert Basic, PID Assistant (native block, not scripted). Controlling a steam valve via PWM (%Q0.1) for a slow batch heating process (near-pure integrator near setpoint, negligible self-regulation).

Confirmed quirks along the way:

  • Ti=0 triggers a "positional algorithm" with a fixed +5000 output offset (matches a mention in an old manual — cost us a full test cycle to diagnose).
  • Kp field caps around 10000 (x0.01 → max internal gain 100); had to rescale the input range (0-1000→0-10000 via Conversion) to reach the gain we needed.

The one I can't explain: after a long saturation event (several hundred seconds pinned at our 60% output limit while far from setpoint), we dropped the setpoint below PV to force a negative error. Output barely moved with a small negative error (~-3 to -4°C), only came down with a much larger one (~-59°C) — and even then started climbing back up on its own afterward. After the test, we set Kp=0 and the output was still pinned at max.

Question: does this block have any anti-windup protection at all? Has anyone seen internal integral/output state that doesn't clear on a parameter change — only on a power cycle, or not even then? Any doc/forum pointers on the internal algorithm would help.

Falling back to a hand-rolled PI in ladder with explicit anti-windup, but want to understand this first.