Siemens S7-400 installation manual Signal Module, Slave, Status interrupt, Substitute Value

Glossary

Segment

→Bus segment

SFB

→System Function Block

SFC

→System Function

Signal Module

Signal modules (SMs) are the interface between the process and the programmable controller. Signal modules comprise digital input and output modules (I/O module, digital) and analog input and output modules (I/O module, analog).

Slave

A slave may only exchange data when requested by a master.

STARTUP

The CPU goes through the STARTUP state during the transition from STOP to RUN mode. It can be set using the mode selector on the CPU, following power-on, or by an operation on the programming device.

Status interrupt

Can be generated by a DPV1 slave. The DPV1 master responds with a call of OB55.

For detailed information on OB57, refer to the “System Software for

S7-300/S7-400 System and Standard Functions” reference manual.

STEP 7

Programming language for writing user programs for SIMATIC S7 programmable controllers.

Substitute Value

Substitute values are values which are output to the process in the case of faulty signal output modules or which are used in the user program instead of a process variable in the case of faulty signal input modules. The substitute values can be specified in advance by the user (for example, maintain old value).

Automation System S7-400 Hardware and Installation A5E00850741-01

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