160 Glossary
WAGO-I/O-SYSTEM 750
753-668/000-004 4FAI 0/4-20 mA Diff PROFIsafe
Manual
Version 1.0.0, valid from HW/SW Version 01/01
S
Safe PLC
A safe PLC (Programmable Logic Controller) is a safety-oriented PLC that
controls safe devices, e.g., F I/O modules.
Safety Function
Function of a machine whose failure can lead to an immediate increase in the
risk(s).
Safety-Related Accuracy
The safety precision contains the maximum tolerance of the components used.
Safety precision is monitored by the F I/O module.
Safety Response Time
- in error-free case
The safety response time in error-free case describes the time from a
change of the input current to the corresponding response in the process
image.
- in case of error
The safety response time in case of error corresponds to the error response
time.
See
also “Error Response Time”.
Sensor
A sensor is used to capture physical units (e.g., switch setting, temperature,
pressure, etc.) and can be connected (if compatible) to the analog inputs of the
F I/O module or with the analog inputs of the F I/O module.
Severity Level of Diagnostics
The severity levels of diagnostics are derived from the PROFINET system
description. According to “Severity Level”, there are errors, maintenance
demanded and warning.
Short Circuit
A practically unopposed conductive connection between two live electrical lines.
SIL (Safety Integrity Level)
The Safety Integrity Level (SIL) is used to assess electrical/electronic/
programmable electronic (E/E/PE) systems in terms of reliability of safety
functions. There are four levels for specifying the requirement for the safety
integrity of safety functions where “Safety Integrity Level 4” is the highest level of
safety integrity and “Safety Integrity Level 1” is the lowest.
Single Fault Safety
Even after an error occurs, the required safety function is still ensured. In other
words, an error does not lead to the loss of the safety function.
