Stack Overflow
Stack Overflow

Questions tagged [plc]

PLC (Programmable logic controller) or programmable controller is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or light fixtures.

1091 questions
4
votes
1 answer

Parsing a Rockwell L5X file

I work in the machine automation industry and extensively uses PLC. I am thinking about a way to automate part of the logic creation which consists a lot of manual typing which I am trying to get rid off. Rockwell uses L5X files which is actually…
1986G1988
  • 132
  • 2
  • 11
4
votes
1 answer

Attaching an event handler to a Com event: InvalidOperationException (S7-PLCSIM)

I'm trying to attach an Event Handler to an Event of a COM Object. But I get an InvalidOperationException. using S7PROSIMLib; private S7ProSim ps = new…
c3ntry
  • 157
  • 1
  • 11
4
votes
2 answers

Which method is generally used to communicate between programs in Structured Text

I am maintaining a project for a PLC written in ST. To implement a new feature I need to let cyclic program A know when an event happened in cyclic program B. How is this generally done in ST? Do I simply use global variables or is there a different…
martinhans
  • 1,133
  • 8
  • 18
4
votes
2 answers

PLC ladder logic sequence

I've spent hours and a trees worth of paper sketching and I haven't been able to stumble upon anything to get me past this problem. I'm able to switch back and forth between two motors but I can't figure out how to turn the motors off while…
internRob
  • 61
  • 6
4
votes
2 answers

How to write an ASCII value into a string in Structured Text for a PLC?

For a PLC program written in Structured Text I need a string which starts with the ASCII values 0x01 0x01 0x01 0x00 0x12. In Java I would do this with: String literal = "\x01\x01\x01\x0\x12"; How can I achieve the same in Structured Text for a PLC?
BetaRide
  • 16,207
  • 29
  • 99
  • 177
4
votes
4 answers

Desktop SCADA Application - Reading and Writing to PLCs through C++

I did my best to search all topics regarding to SCADA and developing your own C++ desktop application to communicate with PLCs, but could not find any recent, or in my opinion, relevant topics that fit what I needed. If I missed them, a link to them…
Josh
  • 41
  • 1
  • 5
4
votes
2 answers

PLC Ladder Logic Outputs

On a single ladder rung how many outputs can you have. If you have more than one. Would it be AND Logic, or OR Logic. Series, or parallel. I'm trying to make six lights flash using timer on delay instructions with a closed input instruction. I will…
Alloys12
  • 69
  • 2
  • 6
4
votes
1 answer

What is cyclic and acyclic communication?

So I've already searched if there was a question like this posted before, but I wasn't able to find the answer I liked. I've been working with some PLCs and variable frequency drives lately and thought it was about time I finally found out what…
Izzo
  • 4,461
  • 13
  • 45
  • 82
4
votes
2 answers

RS232 communication protocol Mitsubishi FX3G PLC

Does anyone know the communication protocol for communication with the RS232 port of a Mitsubishi FX3G PLC? I searched the site of Mitsubishi and Googled, but couldn't find the syntax of the commands to send to obtain the data of specific registers…
Hrqls
  • 2,944
  • 4
  • 34
  • 54
4
votes
1 answer

Purpose of "MOVE" block?

What is the difference between using a MOVE block instead of a direct connection when an output is just to be assign the input value in a function block diagram?
norq
  • 1,404
  • 2
  • 18
  • 35
3
votes
1 answer

Send TCP/IP message from PLC to PC using Ladder Program

Consider the following Ladder Program that checks if a connection is enabled (A202.00) then send a message from the PLC to the PC. The documentation (Omron CX-Programmer) has a severe lack of explanation of the program convention. What I do not…
KMC
  • 19,548
  • 58
  • 164
  • 253
3
votes
1 answer

What is the difference between "Action" and "Method" in TwinCAT 3?

I see options to make an action instead of a method when using function blocks in TwinCAT 3. I am only familiar with methods. What is the difference between the two, and when should you use one instead of the other? I would like to know why the FIFO…
Robert S
  • 33
  • 3
3
votes
1 answer

TwinCAT Motion record travel distance

I need some help writing a function block which I can use to record the travel distance of an axis. This should record every time the axis moves sort of like an odometer, this value will be used for preventative maintenance on the axis. ie greasing…
Chris Smith
  • 35
  • 3
3
votes
1 answer

Unknown PLC function block symbol

I am currently writing a function description for a machine in our manufacturing production. What does this star/sun-like symbol mean?
Bernard Rosencrantz
  • 67
  • 6
3
votes
1 answer

Deploying config files to PLC

Is it possible include arbitrary files (in this case a .csv) from a TwinCAT project direct to the Boot directory of a PLC? By using PATH_BOOTPATH in the file open/read FBs it is possible to load files from this directory in a convenient manner…
Steve
  • 963
  • 5
  • 16
1 2 3
…
72 73