Siemens SIMOCODE pro Manual page 110

Glossary
OEM (Original Equipment Manufacturer)
Original Equipment Manufacturer: In its literal sense, a manufacturer that produces finished
components or products in its own factories but does not retail them itself. However, in many
industries the term OEM is meanwhile employed with a contradictory definition. In the
engineering and automotive sectors, for instance, an OEM is a company that sells the
finished product under its own brand name.
Overload relay
An overload relay is an electronic component that protects an electrical load, such as a
motor, quickly and reliably in the event of overload or phase failure.
PELV (Protective Extra Low Voltage)
Protective measure against electric shock (formerly referred to as "protective extra low
voltage with safe isolation").
In contrast to an SELV circuit, live parts and exposed conductive parts of the equipment may
be grounded and connected to the protective conductor. Safe isolation means that the
primary circuit of the transformer must be separated from the secondary circuit by double or
reinforced insulation. PELV is used whenever operational reasons dictate that live
conductors of the low voltage or bodies of the equipment must be grounded. This is the
case, for instance, if equipotential bonding is necessary to prevent sparking in containers or
hazardous areas. However, owing to the chassis ground, dangerous leakage currents can
flow through the body regardless of the low voltage if a fault occurs in the higher-level power
system.
Performance Level (PL)
According to EN ISO 13849-1, this is the average probability of a hazardous failure per hour.
Five performance levels are specified (a to e) with defined ranges of the probability of a
dangerous failure per hour.
PL "e" corresponds to SIL 3 and is specified as the highest level.
Process Automation (PA)
Automation of continuous production processes. For instance, it controls production
processes in the chemical industry or in water supply systems.
Product lifecycle
Term referring to the anticipated, or historically recorded, development of sales for defined
products during the period for which they are offered in the market. The product lifecycle
describes the five ideal market and product phases, namely the launch phase (1), growth
phase (2), maturity phase (3), saturation phase (4), and degeneration phase (5).
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SIMOCODE pro - Fail-Safe Digital Modules
Manual, 11/2017, NEB631679702000/RS-AA/002