Programming FCs (Functions) and FBs for S7 Ethernet CPs

 

 

 

CPU

Ethernet CP

STEP 7 user program

User data areas

AG_SEND send

AG_RECV receive

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CPU

 

 

 

Ethernet CP

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

STEP 7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

user program

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

receive

 

 

 

 

 

 

 

User data areas

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AG_RECV

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Connection

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

send

 

 

 

 

 

 

 

AG_SEND

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Note

Unless specifically stated otherwise, the information on this and the following pages refers to AG_SEND / AG_LSEND or AG_RECV / AG_LRECV.

Specifying the Data Area on the CPU

When you call an FC, you transfer the address and length of the data area in the CPU. Remember, that the maximum length of the data area depends on the block type and block version being used.

SAG_SEND and AG_RECV

Up to version V3.0 of these blocks, a maximum of 240 bytes could be sent or received. The current block versions allow a data area of up to 8192 bytes for an S7-300. With an S7-400, the FCs AG_LSEND / AG_LRECV must still be used for larger data areas.

SAG_LSEND / AG_LRECV

Using the CPs of the S7-400 and with earlier versions of the S7-300, larger data areas can only be transferred with the FCs AG_LSEND or AG_LRECV. Please check the length of the data area in the product information.

The following table shows the limit values of the various connection types.

SIMATIC NET NCM S7 for Industrial Ethernet

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C79000-G8976-C129–06

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Image 149
Siemens S7 appendix Aglsend / Aglrecv

S7 specifications

The Siemens S7 series represents a cornerstone in the realm of programmable logic controllers (PLCs), developed by Siemens, a leading company in industrial automation. Widely used across various industries, the S7 series offers robust solutions for controlling machinery and processes, thanks to its reliable performance, flexibility, and scalable architecture.

One of the key features of Siemens S7 PLCs is the modularity of their design. Each system can be configured to meet specific application requirements due to the ability to mix various input/output modules, CPUs, and communication processors. This modular approach allows for the customization of systems to suit diverse automation tasks, providing end users with the adaptability required for modern manufacturing environments.

The S7 series encompasses several models, including the S7-1200, S7-300, and S7-1500. The S7-1200 is particularly suited for small to medium-sized applications, offering a compact design and integrated communication interfaces. In contrast, the S7-300 is designed for more extensive and complex control systems, making it ideal for large-scale industrial applications. The S7-1500 stands out with its advanced performance metrics, rich feature set, and high-speed processing capabilities, making it perfect for demanding applications that require real-time control and extensive data handling.

Siemens also emphasizes the importance of communication technologies within the S7 series. With options such as PROFINET, PROFIBUS, and EtherNet/IP, the S7 PLCs can seamlessly integrate into existing automation infrastructures, ensuring smooth data exchange between devices. The incorporation of web-based technologies and cloud connectivity further enables remote monitoring and control of systems, enhancing operational efficiency.

Another notable characteristic of Siemens S7 PLCs is the use of TIA Portal (Totally Integrated Automation Portal), an innovative software platform that simplifies the engineering process. TIA Portal allows users to program, configure, and diagnose their automation devices in a single environment, reducing setup times and improving productivity.

In conclusion, the Siemens S7 series stands out due to its modular design, range of models suitable for various applications, advanced communication technologies, and user-friendly programming software. This combination of features and characteristics makes S7 PLCs a preferred choice for industries seeking reliable and efficient automation solutions. As industrial demands continue to evolve, Siemens S7 PLCs remain at the forefront, adapting to technological advancements and setting benchmarks in the automation field.