What is the PLC programming language STL?

What is the PLC programming language STL?

PLC manufacturers have designed instructions and programming components specifically for programming sequence control programs.

Among them, STL is the Step Ladder Instruction.

SET: Set to close the contact.

RET: Reset to disconnect.

When using STL instructions, you should pay attention to the following issues:

1) The contacts connected to the STL contacts should use the LD or LDI instructions, that is, the LD point is moved to the STL contact. On the right side, until the next STL instruction or the RET instruction appears, the RET instruction causes the LD point to return to the left bus. The circuits driven by each STL contact are generally put together, and the RET instruction must be used when the last circuit ends.

2) STL contacts can directly drive or drive the coils of Y, M, S, T and other components through other contacts. STL contacts can also set or set Y, M, S and other components. reset.

3) When the STL contact is open, the CPU does not execute the circuit block it drives, that is, the CPU only executes the program corresponding to the active step. When there is no parallel sequence, there is only one active step at any time, thus greatly shortening the scan cycle.

4) Since the CPU only executes the circuit block corresponding to the active step, dual coil output is allowed when using STL instructions, that is, several coils of the same component can be driven by different STL contacts. In fact, within one scan cycle, only one of several OUT instructions for the same component is executed.

5) STL instructions can only be used in status registers. When there is no parallel sequence, the STL contact of a status register can only appear once in the ladder diagram.

6) MC and MCR instructions cannot be used in STL contact driven circuit blocks, but CJP and EJP instructions can be used. When the CJP instruction is executed to jump to a circuit block driven by a certain STL contact, regardless of whether the STL contact is in the "1" state, the circuit after the corresponding EJP instruction is executed.

7) Like ordinary auxiliary relays, you can use LD, LDI, AND, ANI, OR, ORI, SET, RST, OUT and other instructions for the status register. At this time, the state device contact The drawing method is the same as that of ordinary contacts.

8) If the instruction that sets the state device is not in the circuit block driven by the STL contact, the system program will not automatically reset the state device corresponding to the previous step when the set instruction is executed.

STL in the PLC programming language is a step contact instruction, used in step ladder diagrams.

1. PLC programming is an electronic system for digital operation. It uses a programmable memory to store instructions for performing logical operations, sequence control, timing, counting and arithmetic operations, and controls various types of operations through digital and analog inputs and outputs. Other machinery or production processes. PLC works using the method of "sequential scanning and continuous looping".

2. STL is the Chinese name Standard Template Library, a collective name for a series of software developed by HP Labs. STL is a collection of "containers". STL is also a collection of algorithms and other components. The purpose of STL is to standardize components so that they do not need to be redeveloped and off-the-shelf components can be used. There are many versions of STL, common ones include HP STL, PJ STL, SGI STL, etc.

What is the full spelling of the Siemens PLC programming language "Statement List (STL)"?

PLC manufacturers have designed instructions and programming components specifically for programming sequence control programs.

Among them, STL is the Step Ladder Instruction.

When using STL instructions, you should pay attention to the following issues:

1) The contacts connected to the STL contacts should use the LD or LDI instructions, that is, the LD point is moved to the STL contact. On the right side, until the next STL instruction or the RET instruction appears, the RET instruction causes the LD point to return to the left bus. The circuits driven by each STL contact are generally put together, and the RET instruction must be used when the last circuit ends.

2) STL contacts can directly drive or drive the coils of Y, M, S, T and other components through other contacts. STL contacts can also set or set Y, M, S and other components. reset.

3) When the STL contact is open, the CPU does not execute the circuit block it drives, that is, the CPU only executes the program corresponding to the active step. When there is no parallel sequence, there is only one active step at any time, thus greatly shortening the scan cycle.

4) Since the CPU only executes the circuit block corresponding to the active step, dual coil output is allowed when using STL instructions, that is, several coils of the same component can be driven by different STL contacts. In fact, within one scan cycle, only one of several OUT instructions for the same component is executed.

5) STL instructions can only be used in status registers. When there is no parallel sequence, the STL contact of a status register can only appear once in the ladder diagram.

6) MC and MCR instructions cannot be used in STL contact driven circuit blocks, but CJP and EJP instructions can be used. When the CJP instruction is executed to jump to a circuit block driven by a certain STL contact, regardless of whether the STL contact is in the "1" state, the circuit after the corresponding EJP instruction is executed.

7) Like ordinary auxiliary relays, you can use LD, LDI, AND, ANI, OR, ORI, SET, RST, OUT and other instructions for the status register. At this time, the state device contact The drawing method is the same as that of ordinary contacts.

8) If the instruction that sets the state device is not in the circuit block driven by the STL contact, the system program will not automatically reset the state device corresponding to the previous step when the set instruction is executed. PLC programming language classification ~

Ladder diagram language, Boolean mnemonic language, function table diagram language, function module diagram language and structured statement description language, etc. Ladder diagram language and Boolean mnemonic language are basic programming languages. What is the difference between LAD programming and STL programming in S7 series PLC programming language?

STL statement table programming can easily see the order of statement execution, and is often used in complex calculations. However, STL with complex logic has poor readability. LAD is intuitive, the logical relationship is clear at a glance, and it is easy to read. What is the full spelling of "Statement List (STL)" of Siemens PLC programming language? Thanks!

STL (Standard Template Library)

Statement List (STL)

The hardware system and internal resources of the 300/400 series PLC are introduced in Chapter 3 The addressing mode and instruction system of S7-300/400 series PLC are explained with examples, focusing on the use of statement list (STL) and ladder diagram (LAD) instructions. Chapter 4 introduces the programming environment of STEP7 software and PLC. Applying the content and methods of system design, Chapter 5 introduces the use of STL. How to learn PLC programming language

Let’s talk about the experience of learning PLC. Before I started working on PLC, I really didn’t even know what a PLC did. By chance, I was recruited into an automated production line workshop, which was a welding line. I started working on PLC and welding robots directly. Before you even have time to buy the PLC book, a lot of device information is placed in front of you. Everyone looks at you with complicated eyes looking forward to it ~ their heads are getting big. At the beginning, I didn’t know how to use the S7 software. It was still the English version of 5.2. I looked directly at the ladder diagram and the normally open and normally closed points. The most difficult thing was that I couldn’t figure out why the normally open point was connected on site and how to do it in the program. A closed-door space...my head is full of questions that no one can ask. At that time, I was studying robot debugging during the day, and when I returned to the rental house at night, I read the program. There was no PLC reference book around me, so I looked at the help that comes with Simatic Manager. I even installed a word master to act as a word translator and found that it was helpful. It contains detailed descriptions and examples of various instructions (LAD/STL/FBD), and then I found a lot of things I was eager to know, such as CPU internal storage usage, argument types, uploading, downloading... etc., and slowly became more and more familiar. The more you discover, for example, if you open a dialog box and click the help group in the lower right corner, help will pop up, and it will focus on how to operate this dialog box. There is also the little arrow with a question mark on the toolbar, which is online help. Later, I installed the Chinese version of STEP7V5.4, which solved the language problem and seemed much more convenient. Personally, I feel that after seeing more and touching more, combined with the basics of electricity, I gradually understand many unclear software and hardware things. Sometimes I suddenly find a clear answer and verify that it is correct. I was very excited and interested. Reading the program was very simple at first, just an OB1 block, a few I/O/M points, and then some more functional FCs, and more instructions. If you encounter something you don’t understand, just look at the help, so the urge to buy a PLC book disappeared. I put it off again and again, and I still haven’t bought it until now. Later, I started working on some very complex programs, with a lot of function blocks and data blocks. When I looked hard enough, I discovered a lot of unknown things. . . In this circle, I read more and more programs and circuit diagrams. From the initial hard-wired system (one input point corresponds to one signal line) to the bus system (Profibus field bus), I spend a lot of time online every day. They spend energy and time solving questions in their minds and faults on the production line, checking relays, and measuring broken wires. Some domestic devices are simply installed once, without any consideration for subsequent maintenance. The wiring and labels are messy, and even the programs given have no symbols. Comment, angry and tired. Later, I moved to a new home and installed network cables, so I no longer had to go to an Internet cafe. So I went to the official website to download information, hardware manuals, and software packages like crazy, then upgraded the computer software, went to the workshop to compare, look at the modules, and got a few modules. The components and CPU were assembled in the office, connected to the computer, and even disassembled for "study" without worrying about damage.

Because I can stand alone, more and more people ask questions. At first, I was a little hesitant. After all, I have gained experience through hard work. It took a long time to understand some things, and I explained them to others in two minutes, but Later I found that this was not possible and I stopped moving forward, so I talked about it without reservation, and then I went to discover and learn new things. . . . Over the past few years, all the hard work has been in vain. The basic skills, experience summaries accumulated continuously, especially the ability to think, comprehend and self-study are the best rewards for those unknown hard work and late nights. What are the plc programming languages?

PLC has five standardized programming languages: three graphical languages: sequential function chart (SFC), ladder diagram (LD), function module diagram (FBD) and statement list (IL). ) and structured text (ST) two text languages

The two most commonly used programming languages ??are ladder diagram and mnemonic language table.

Use ladder diagram programming because it is intuitive and easy to understand, but requires a personal computer and corresponding programming software; use mnemonic format to facilitate experimentation, because it only requires a simple programmer , without having to use expensive graphics programmers or computers to program.

There are several plc programming languages ??

There are mainly the following 5 programming languages:

1. Ladder Diagram Language (LD)

2. Instruction List Language (IL )

3. Functional module diagram language (FBD)

4. Sequential functional flow chart language (SFC)

5. Structured text language (ST )