ifm
System Manual
ecomat
mobile
PDM360NG (CR1080, CR1081, CR9042) Target V01
2011-07-28
Glossary of Terms
448
Disadvantages of flash memories
A storage cell can tolerate a limited
number of write and delete processes:
- Multi-level cells: typ. 10 000 cycles
- Single level cells: typ. 100 000 cycles
Given that a write process writes memory
blocks of between 16 and 128 Kbytes at
the same time, memory cells which require
no change are used as well.
FMEA
FMEA =
F
ailure
M
ode and
E
ffects
A
nalysis
Method of reliability engineering, to find
potential weak points. Within the framework of
quality or security management, the FMEA is
used preventively to prevent faults and
increase the technical reliability.
FRAM
FRAM, or also FeRAM, means
Fe
rroelectric
R
andom
A
ccess
M
emory. The storage
operation and erasing operation is carried out
by a polarisation change in a ferroelectric
layer.
Advantages of FRAM as compared to
conventional read-only memories:
non-volatile,
compatible with common EEPROMs, but:
access time approx. 100 ns,
nearly unlimited access cycles possible.
Functional safety
Part of the overall safety referred to the
EUC
and the EUC control system which depends on
the correct functioning of the electric or
electronic safety-related system, safety-related
systems of other technologies and external
devices for risk reduction.
H
Harm
Physical injury or damage to health.
Hazard
Hazard is the potential source of harm.
A distinction is made between the source of
the hazard, e.g.:
- mechanical hazard,
- electrical hazard,
or the nature of the potential harm, e.g.:
- electric shock hazard,
- cutting hazard,
- toxic hazard.
The hazard envisaged in this definition is either
permanently present during the intended use
of the machine, e.g.:
- motion of hazardous moving elements,
- electric arc during a welding phase,
- unhealthy posture,
- noise emission,
- high temperature,
or the hazard may appear unexpectedly, e.g.:
- explosion,
- crushing hazard as a consequence of an
unintended/unexpected start-up,
- ejection as a consequence of a breakage,
- fall as a consequence of
acceleration/deceleration.
Heartbeat
The participants regularly send short signals.
In this way the other participants can verify if a
participant has failed. No master is necessary.
HMI
HMI =
H
uman
M
achine
I
nterface
I
ID
ID =
Id
entifier
Name to differentiate the devices / participants
connected to a system or the message
packets transmitted between the participants.
IEC user cycle
IEC user cycle = PLC cycle in the CoDeSys
application program.
