Appendix A
Panel PC 2100 user's manual V1.17
329
A.2 Abbreviations
Abbreviation
Stands for
Description
Normally closed
Normally closed relay contact.
NC
Not connected
Used in pinout descriptions if a terminal or pin is not connected on the module
side.
ND
Not defined
In technical data tables, this stands for a value that is not defined. This may
be because a cable manufacturer does not provide a value for certain technical
data, for example.
NO
Normally open
Normally open relay contact.
TBD
To be defined
Used in technical data tables when there is currently no value for specific tech-
nical data. The value will be provided at a later point in time.
B
10D
-
Number of cycles before 10% of the components have experienced hazardous
failure (per channel).
MTTF
D
Mean time to dangerous failure
Average time before hazardous failure occurs (per channel).
DC
Diagnostic coverage
Diagnostic coverage
PL
Performance level
Discrete level that specifies the ability of safety-related devices to perform a safe-
ty function under foreseeable conditions.
PFH
Probability of failure per hour
Probability of failure per hour.
SIL
Safety integrity level
Safety integrity level
Table 291: Abbreviations used in this user's manual
A.3 Viewing angles
For the viewing angle values of display types (R, L, U, D), see the technical data of the individual components.
R
L
U
D
6 o'clock direction