How to Use Unity Pro XL: Sample Code with Loops, Delays, and More

bajsmannen mentioned that they did not receive helpful advice and expressed frustration with starting with a ladder. They questioned if there is limited information available online regarding the issue. Despite someone offering example code but failing to send it, the original poster wondered why a new thread on the same topic was started. However, it is important to take the time to search for documentation. For instance, a quick search yielded useful information in the ST section of Schneider Electric's website. You can find more details in this document: http://download.schneider-electric....533442681&p_File_Name=33003101_K01_000_17.pdf.

• 30-08-2024
• tragically1969

Is there a more straightforward way to create a delay in programming? Many languages offer a simple function such as "waittime" or "delay" to achieve this. I attempted using %S6, but I believe a timer is necessary in this scenario. I am struggling to grasp its functionality. When neither PB_1 nor PB_2 are pressed, I set DIOD_1 to 1 and DIOD_2 to 0. However, if either PB_1 or PB_2 is pressed, I want to delay for 2 seconds before switching DIOD_1 to 0 and DIOD_2 to 1. This process seems unnecessarily complicated due to the timer requirement. In a different programming language, this task would be much simpler.

• 30-08-2024
• bajsmannen

In the code provided, the variable run_timer1 is set to 0 initially. If either PB1 or PB2 is pressed and the timer is not yet done, run_timer1 is set to 1. A TON_0 timer is then activated with a time of 2 seconds, using run_timer1 as the input and setting timer1_done as the output. Once timer1_done is true, a specific action is performed. The code then resets run_timer2 to 0 and checks if either PB1 or PB2 is pressed. If so, run_timer2 is set to 1. Another TON_1 timer with a duration of 2 seconds is started with run_timer2 as the input and timer2_done as the output. When timer2_done becomes true, a continuous action is executed after a 2-second delay. It is important to reset the outputs back to 0 at the right time, as constantly maintaining non-zero outputs may not be efficient. By recognizing the limitations of using ST for certain logic types, one can appreciate the advantages of Ladder and FBD programming languages.

• 30-08-2024
• V0N_hydro

V0N_hydro mentioned the following code snippet for timer operations: run_timer1 :=0; if ((PB1 OR PB2) and not timer_done) then run_timer1 :=1; end_if; Implementing TON_0 (in:= run_timer1, PT := t#2s, Q=>timer1_done); Once timer1_done is true, specific actions will be executed once. run_timer2 :=0; if ((PB1 OR PB2)) then run_timer2 :=1; end_if; Using TON_1 (in:= run_timer2, PT := t#2s, Q=>timer2_done); Upon completion of timer2, continuous actions will occur every 2 seconds. Ensure to reset outputs to 0 as needed to avoid errors. Although some may consider ladder logic outdated, its efficiency and applicability in various scenarios surpass the complexities of ST programming.

• 30-08-2024
• tragically1969

Although this thread may be old, it's valuable to address the question raised by the original poster. Even though the OP may no longer be active, other users might come across this thread with similar inquiries. In the discussion, a user named bajsmannen raised a query about implementing a simple delay function in a programming environment. While it may seem straightforward in other languages, the challenge lies in the unique characteristics of PLC programming. Unlike traditional programming languages like C, PLC code operates in a loop where all instructions are executed on each pass through the loop. This loop, known as a scan cycle, must complete within a specified time frame to prevent the PLC from halting due to a watchdog timeout. In a PLC environment, it's crucial to understand that code execution cannot have long delays that pause the scan cycle. Instead, PLC code must be designed to function in a continuous loop, ensuring that all instructions are processed within each scan cycle. Aligning with the PLC's scan cycle structure is key to successful programming in this environment. By adjusting the mindset from linear programming to the loop-based nature of PLCs, users can navigate the unique challenges posed by PLC programming. To illustrate, a simplistic model of PLC programming is depicted, where the PLC Executive process manages the scan cycle and ensures the timely execution of all instructions. A TON timer is utilized to handle time-related functions within the PLC code, accumulating time values and triggering actions based on preset durations. It's essential for programmers to grasp the concept of scan cycles and how each pass through the loop impacts code execution in a PLC environment. Overall, adapting to the nuances of PLC programming entails a shift in perspective, moving away from traditional programming paradigms towards a more loop-centric approach. By embracing the distinctive characteristics of PLC programming, users can effectively navigate the complexities of coding in a PLC environment.

• 30-08-2024
• drbitboy

In traditional computer programming, the concept of "state" refers to the current execution point of the machine in the code. Flow charts are commonly used to visually represent this process. By pausing the processor, you can determine its previous actions based on its position in the code sequence. To simultaneously handle multiple tasks, parallel threads of execution are necessary. Contrary to conventional languages, in most Programmable Logic Controller (PLC) languages, the state is stored in data rather than in the code. By monitoring which relays are activated or deactivated, you can track the machine's cycle progress. Multiple processes can run concurrently by assigning specific relays to each task, a practice observed in LD, FBD, and ST programming languages. In ST programming, timers operate similarly to LD timers, running continuously until the assigned timing is complete. The end of a timer cycle is signified by a change in associated data, often referred to as the "Done bit." The challenge often lies in understanding how PLC programming languages function, rather than with the ST language itself. SFC programming introduces a new approach, where the processor's location in the code dictates the system's state. This offers both power and risk, requiring skill to achieve desired outcomes without errors. It is beneficial for PLC programmers to incorporate techniques for encoding state transition diagrams into languages like LD into their skill set. These methods can enhance efficiency and effectiveness when working with PLC systems.

• 30-08-2024
• Corsair