Glossary

A

Address

An address is the identifier for a specific area of memory on which an instruction acts.

Examples: Input I 12.1; Memory Word MW24; Data Block DB3.

Analog Module

Analog modules convert analog process variables (for example, temperature) into digital values that can be processed in the CPU or they convert digital values into analog manipulated variables.

B

Backup Battery

The backup battery ensures that the user program in the CPU is not lost in the event of a power failure and that defined data areas, bit memory, timers, and counters are also retained.

Bit Memory (M)

A memory area in the system memory of a SIMATIC CPU. This area can be accessed using write or read access (bit, byte, word, and double word). The bit memory area can be used by the user to store intermediate results. It can be accessed bit by bit, byte by byte, word by word, or double word by double word.

Building Ground

The connection between data processing equipment and ground, whereby no unacceptable functional interference to data processing equipment is caused by external effects, such as interference caused by power systems. The connection must be in the form of a low-noise ground.

Bus segment

Entity of a serial bus system, coupled via repeaters.

Automation System S7-400

Hardware and Installation

Glossary-1

A5E00850741-01

 

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Siemens S7-400 installation manual Address, Analog Module, Backup Battery, Bit Memory M, Building Ground, Bus segment