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This sub is dedicated to discussion and questions about Programmable Logic Controllers (PLCs): "an industrial digital computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, robotic devices, or any activity that requires high reliability, ease of programming, and process fault diagnosis."


This sub is dedicated to discussion and questions about Programmable Logic Controllers (PLCs): "an industrial digital computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, robotic devices, or any activity that requires high reliability, ease of programming, and process fault diagnosis."

On topic subjects

  • News and articles about PLCs
  • Questions about PLCs
  • Homework help; but make it clear it's homework
  • PLC internship, employment and education questions

Off topic subjects


  1. Be civil: do not insult; no all-caps, no excessive "!" and "?", please.
  2. Submissions must be on topic
  3. If asking a question, ask the actual question, fully yet concisely, right in the title
  4. No spam; no self-promotion (*); no commercial content. Any ads (offer or wanted) go to the weekly thread
  5. No shit posts (memes - pictures with superimposed text - are OK)

(*) At mods' discretion, certain self-promotion submissions from people who contribute to this sub in other ways may be allowed and tagged with the "Self-promo" flair

Complete rules:/r/plc/about/rules/

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82,060 Subscribers


FTOptix Scroll View Container??

I’ve made HMIs on a 1920x1080p size. However I’ve been asked to make them compatible with different window sizes. The person who asked him suggested I use the Scroll View Container. I’ve been messing around with it and trying to find docs/ppl talking about with not much luck. My plan was to wrap my main screen stuff in a scroll View container since it contains the panel loader for all the other panels. If I set “Enable Zoom” to true it just doesn’t display anything. Has anyone used this feature that can give some guidance/tips and tricks

03:04 UTC


Perfect panel

1 Comment
02:43 UTC


DCS Control System with ISA 101 standards

00:21 UTC


I got a maybe (Headhunter) Job offer

I am no spring chicken at this point. This job gets me a 30-40k raise from where I am at right now (Currently working for a large OEM that packages controls). It sounds like it is a job shop maybe. It means I would be driving an hour each way every day. How many of you would say "Yep!"? Ohio.

Control Systems Design: Develop and implement control strategies for various processes, ensuring optimal performance and compliance with safety standards.

PLC Programming: Program and troubleshoot Programmable Logic Controllers (PLCs) to control and monitor equipment.

SCADA Systems: Design and maintain Supervisory Control and Data Acquisition (SCADA) systems to monitor and control manufacturing processes.

The ideal candidate will have a strong background in control systems design, implementation, optimization, and will be responsible for maintaining and updating the Distributed Control System (DCS)  as needed. The Controls Engineer will play a key role in ensuring the reliability and performance of our manufacturing  processes through effective design, maintenance, and upgrades of control systems.

This position offers 3+ weeks of PTO, $0 medical benefits for your entire family, annual bonus, 401k match and a competitive base salary (170k-180k BOE).

01:38 UTC


Is anyone here freelance/independent?

Do you earn a decent living?

18:53 UTC


does Step 7 professional in TIA18 contain safety basic or advanced

hi All

Really confused what is the difference between Safety basic and safety advanced.

Does TIA 18 already have advanced version by default if Step7 professional is installed?


17:12 UTC


PI Datalink Data Retrieval

Hi All, I recently started using PI Datalink. I’m new to PI Datalink. So I’m stuck trying to figure out a way to just extract the peak values. When I extract the data into excel using the excel add in, sample size between each cycle is inconsistent, the timestamps are inconsistent making it really hardly to apply a formula and extract the peak value. Also there exists noise between each cycle which I don’t want. If any experts in PI Datalink can help me here, that would help super helpful. Thanks

15:42 UTC


Keyence KV-N24DTP and Mettler-Toledo Balance

Does anyone have any experience with connecting RS-232 communications between a Keyence Nano (with RS-232 cassette) and a Mettler Balance (MA-103)? I'm not entirely sure what settings i need to have set on the balance, other than the com protocols. I've reached out to Mettler, but I'm getting bounced around. Keyence helped me with the code, but I'm still not getting a response from the Balance.

Any suggestions or pointers would be greatly appreciated. Please let me know if the mnemonics would help to see as well or even the txt of the ladder

14:05 UTC


Branch around P_TRIG instruction? (TIA Portal Programming Question)

13:16 UTC


Tags and...

So Im working Quick 2 by schneider and cant find where to determine tags, change NO and NC inputs and how to put a wire.

11:01 UTC


Stuck panelview button

I have occasionally run into a stuck momentary pushbutton on my 2711P-T10C22D9P screen. I can tell that the button is stuck on due to there being a green border on the momentary button, even with the area not touched. Pressing the button does not un-stick it, all other buttons on the screen work fine. This occurred occasionally out of the box new (its not a new hardware problem). Unfortunately this button is on one of the always on top menu displays that is loaded on startup, I cannot navigate away from this screen. This controller tag is not being written to inside the plc logic.

Is there a command that can be used to close everything and reload {screen 1} as the background and {screen100} on-top? I do not want to call {screen100} by itself as I am concerned about a month later with multiple instances of the same screen being opened.

Techconnect suggested rebooting the screen, I'd rather not go to this extreme, and have some "reload" button for just a 3 second display reload instead of a 3 minute reboot...

10:38 UTC


Nonlinear sensor

Guys I'm fairly new to plc programming, does anyone know I could get an analog input with a s71200 from an 02 sensor that has a logarithmic relationship, it has a range of 0...95% reading and an output of 4...20mA

09:58 UTC


HMI Step Visualistation (Siemens 1500 & Tia)

Hello fellow PLCers,

what is the best practice to textually show on the HMI what step in the programming sequence is active? The sequence is programmed as an FB and gives the step as an integer Out Variable. The PLC is connected via Profinet to the 7'' Siemens HMI.

If for example step 3 is active, then I want the text to show "machine has started" or something.

The reason I'm asking is that because initialy I wanted to store my step variable as string and do the whole programmic logic on evaluating the string and then simply use that to show what the machine is doing on the HMI. My teacher said that is bad for the cycle time and inefficient. Is that true? What is the optimal solution for this?

07:54 UTC


Help with Holding brake S120

Hi! Im using sinamics s120 cu310-2pn with PM240-2, i wanna know how to control the holding brake directly via the chassis size module !! Do i just need to set the p1215=1 and connect the the brake relay to the power module (because it has a specific output for the brake)

1 Comment
07:39 UTC


Siemens Unified - Email function

Im looking for a email function for Siemens Unified RT.
I have only found that it should be an example on DVD2, can't find anything there either
Has anyone done that before, cant find any good information?

1 Comment
07:26 UTC


AWL code alignment with TiA Portal

Hi All,

I need to develop a series of different robots to a new PLC controller. Therefore we decided to export general AWL code from old robots' test bench and develop the so called AWL code. Then we need a software which recognize which part of the code has been changed, do they align with ISO 13849 standard? If yes, do the tests and report all the so called process.
One of the candidates of us is Siemens TiA Portal. I have no idea about that and don't know if it's suitable or not. If it is, how can I know which CPUs do I need to use. About Step(N) and WinCC, I also have no idea that how they can help me.
I would appreciate if you can help me since Simense website is really hard to understand things.
If you have questions, please let me know.
Best Regards

07:21 UTC


Not Sure If PLC Is What I Need

I want to collect and store data from multiple sensors using rs485. Do I need a PLC or something else? It would be greatly appreciated if you can point me in the right direction.

Thanks for the replies everyone. Here are some more details:

The sensors have the standard Modbus protocol specification. It says also that they use 485 Modbus-RTU communication protocol.

I will have four sensors. I want to log each sensor data with date, timestamp, sensor values, probably every 30 seconds. I would like to save data to CSV.

It is critical data, I do not want to miss data. It is an outdoor application. The setup will be protected from sun and rain but it is not feasible to setup a full computer or laptop.

03:04 UTC


Allen Bradley Powerflex 70 Accel/overshoot

So I'm probably out of my depth here so looking for some help. This is probably going vague so please let me know what other info is needed to help.

I have an AB power flex 70 controlling a 50 HP motor that is coupled to an axial piston pump. Problem Im having is that the motor accelerates so quickly that it causes a pressure spike in the piping thus faulting the machine. The machine has a flow meter that provides an analog input back to the drive. The goal is to maintain a specified flow rate that is monitored by PLC.

Looking at the drive parameters I see that parameter for accel P140 is set to 3s. If I extended this time to 10-15 seconds would this would this cause the ramp to be more gradual or am I misunderstanding the function of this parameter. Assume there are some PI parameters that could help control the overshoot too but I don't want to start randomly changing these.

00:09 UTC


RSLogix 500 Pro individual download

Is there a way to download just one Program File of my entire project? Because I don't want to overwrite some data that has nothing to do with my modifications.

19:20 UTC


How to change PID Output to Zero when Rung is OFF

I'm using RSLogix 5000. I have a PID block that is using tieback. When the rung is OFF, I want the output of the block to go to zero. Currently, it retains the value being used last. Can someone please tell me what I'm missing?

19:07 UTC


Similar fields with little to no travel

It's just another day sitting bored in a sweaty factory during an install away from home. I'm used to it - but more and more I find myself completely over it.

The obvious answer is to quit doing integration - but working end user in my part of the south rarely snags you $100k+ without a mountain of overtime.

To those who have escaped - what are some similar fields with an adjacent skillset to controls that pay at or above six figures? Bonus points if it's somewhat hybrid or remote.

I know the typical answers... Something more SCADA focused or OT security maybe. Those two either rarely pay much; or in the latter case just seems hard to break into.

18:33 UTC


How to make alarms false/disabled condition during a phase?

This is for Rockwell Studio 5000 software.

Apologies if this is a silly question, but I have a phase I’m building out where I need to disable certain alarms between certain steps of the phase. These alarms are your BOOL .DevHHAlarm, .DevLAlarm etc in a PID instruction or alarms in a VSD instruction, so there’s no .Disable option for disabling them.

I’m struggling with how to write Ladder Logic code to say, if a step is EQU (Equal) to this, set these alarms to false so that they can’t go off during those phase steps.

I have the Equal part down using the EQU instruction, but I don’t know about the “alarms to false part.”

Any help would be appreciated!

16:43 UTC


Looking for AutoMax advice (PSC3000)

I'm on an upgrade project for a system with several old AutoMax plcs, and only some of them are being replaced.

if anyone has any advice for setting up data in one of these controllers to be written to, I want to make sure I am doing it right.

TLDR I need to modify the .CNF (configuration) file in one of the controllers that will remain in place, so that data that it was reading from a controller being replaced can now be written to it by the new controller. [this is necessary because of the bridging hardware limitations]

As near as I can figure it, two plcs would read data from each other, but neither performed any write functions. Now, we will need the new controller performing both read and write functions, as the old controller will not be able to read from the new through the translation gateway.

Device to remain: DROP 10
Device to be replaced: DROP 4

This is a section of the configuration file which is read by other controllers.

This is a section of the configuration file where the controller was reading from the machine I am replacing

finally, this is a section of new configuration that I hope will replace the above; defined tags above register 32 that (can?) be written to by the new controller.

The advice I am looking for is whether this is the procedure for writing data to the PSC-3000 or should I do it some other way?

I do have a (paper) copy of the manual, but no experience or other code to examine for comparison.

16:17 UTC


What training sites you subscribe to, for keeping your skills up to date?

I love automation school by Shawn Tierney & looking for similar training courses for self learning & continuous improvement. Got laid off recently & have some downtime to catchup on any knowledge gaps, learn new content. Usually I just read user manuals, watch some youtube videos, look up content on udemy but looking for proper courses I can take to add new skills with focus on PLC, HMI, SCADA, Databases, Communication protocols, Networking & Hardware. Most of my training is on the job & hands on experience with very little time to get any questions answered so I want to utilize this time to brush up on my skills & fill any gaps.


15:35 UTC


Releasing/giving all project files to customers

How do you go on about releasing all project files, configurations etc. to customers. I have a particular customer that are sure they can "optimize" my code and have the necessary know-how of the platform in question. I am very dubious about that statement but I am always in for dishing out humble pie.

Because the first thing they will do is modify the machine I am interested in what's the standard for situations like this.

I have a basic agreement in place, no more warranty, no more service calls, But I have to give them offers for anything related to the project if the ask for it so I am not totally severing relations with them.

I will be conducting a day of orientation around the project for the engineers and giving them the full project documents I have. for return I am asking for 10% of the value of the total project for the source documents.

Given how I will lose revenue on maintenance over the lifetime of the machine I think this deal is a steal for them.

Do you give away source files for free? or do you ask for some price ? what about warranties service calls etc.

14:54 UTC


Simulating Faults

Hey guys, I work with rockwell studio 5000 and I am working on a PLC Trainer to elevate the abilities of our technicians. The concept isn't to teach them HOW TO code but more troubleshooting and reading code skills. My concept is to introduce some sort of failure mode at some point during a sequence and have a method to recover using the 8 inputs on the machine to input a decimal number solution so that no coding changes are actually necessary. I have a few ideas but I was curious if anyone has done something like this before or has some ideas on some simulated events I can trigger to take place.

14:11 UTC


Siemens ET 200pro issues

ran into a weird issue yesterday that's got me stumped, hoping for some additional input/thoughts/suggestions.

Working with a system with 100 or so ET 200pro IO systems - 2 in particular are where the issues lie. basically each of the interface modules seem to have no power (none of the status/diagnostic LEDs are on and they are not visible on the network), but all of the subsequent connected modules (DI, DO, RFID, motor starters) appear normal.

These are the last two in a group of five powered in series with one another, and parallel to another group of two. if I remove the power cable from the 5th device and then remove/restore power to the 4th, the 4th device powers on normally and is visible on the network again. However as soon as I reconnect the 5th device, the 4th device drops off of the network and all of the LEDs turn off.

Suspecting an issue with either the backplane or one of the IO modules, I removed the interface module and connection module and put the termination piece on it and reconnected to PN and 24v, and still experienced the same issue. So I grabbed a spare interface module, still the same thing. Swapped in a known good connection module, still no change. if I bypass the 4th device by connecting, the 5th one still does not properly power on BUT the 3rd one does not shut off. I've also put known good parts on the 4th group but it didn't make any difference.

If I power cycle the control cabinet, everything powers up as normal until all faults are acknowledged and then the two troublesome modules lose connection/power once again.

If anything isn't clear or more info would be helpful let me know and I'll add what I can. I appreciate any help

13:41 UTC


Does micrologix 1100 support modbus tcp


Hello folks, I am new to A-B, Does Micrologix 1100 support modbus tcp/ip communication or any other IP-based protocol. I know that Micrologix 1400 does support modbus tcp

Note: the screenshot is from chatGPT

13:35 UTC


See below. This is how we are implementing adding traceability to existing stations. Is there a better to do it?

We have couple of production station which did not have any traceability before. So, currently we are adding traceability using scanners and LabVIEW.
How is this done at your place?
Here we scan a code which is stored in LabVIEW and checked of there is a duplicate.
The LabVIEW also generates data based on week, month etc.
The scanner is connected through a rs232 to eth converter -- hub---to pc.

Forgot to add.
LabVIEW also gives output to plc like scan received, scan good, scan bad, scan mismatch.

12:57 UTC

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