Programming FCs (Functions) and FBs for S7 Ethernet CPs

5.2.2Parameters for Specifying a CPU Data Area (input parameters)

Specifying the Data Area on the CPU

When you call an FC, you transfer the address and length of the data area on the CPU in which the user data are available or will be stored or which can contain further parameter information.

The ANY pointer data type is used to address this area. For more detailed information on this data type, refer to the STEP 7 online help under the topic “Format of the Parameter Type ANY”. You will also find a detailed description of the ANY point in /21/.

5.2.3Status Information (output parameters)

For status evaluation, the following parameters must be evaluated in the user program:

SDONE or NDR

These parameters (DONE with send jobs and NDR with receive jobs) signal (successful) completion of the job.

SERROR

This indicates that the job could not be executed error-free.

SSTATUS

This parameter supplies detailed information about the execution of the job. Status codes can be returned during execution of the job (DONE=0 and ERROR=0).

Evaluating Status Codes

Remember that the status codes DONE, NDR, ERROR, STATUS are updated at each block call.

Status Codes during CP Startup

With a complete restart or restart of the Ethernet CP (after activating a switch on the module), the output parameters of the FC are reset as follows:

SDONE = 0

SNDR = 0

SERROR = 0

SSTATUS = 8180H for AG_RECV / AG_LRECV or 8181H for AG_SEND /AG_LSEND

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Siemens S7 appendix Parameters for Specifying a CPU Data Area input parameters, Status Information output parameters

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.

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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.