Parker iqan-mc3, User Manual

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52
Failure modes
Appendix B
Instruction book, IQAN-MC3
Failure modes
The following tables have information about the actions taken by the IQAN-MC3 when
certain failure causing conditions occur.
Failure modes for single inputs
N
OTICE
For safety functions, VIN is the only input type that may be used without another input
as comparison.
Sensor failure modes are not included in these tables.
Key to symbols
• = detection leads to error status on input. See IQANdesign user manual.
* = VIN error detection limits are application dependent, and must be used for safety
functions. See IQANdesign user manual.
** = Use a secondary diagnostic channel for error detection.
Voltage input
Digital input
Failure mode Detected Comment
VIN open • Detection only if valid signal range is
limited
VIN short circuit to +BAT • Detection only if valid signal range is
limited
VIN short circuit to signal > high error
detection voltage * • Detection only if valid signal range is
limited
VIN short circuit to signal within error
detection limits * Incorrect input **
VIN short circuit to signal < low error
detection voltage * • Detection only if valid signal range is
limited
VIN short circuit to -BAT • Detection only if valid signal range is
limited
Failure mode Detected Comment
DIN open Input low **
DIN short circuit to +BAT Input high **
DIN short circuit to signal > high trigger
level * Input high **
DIN short circuit to signal within low to
high trigger level range * Undefined (input high or low) **
DIN short circuit to signal < low trigger
level * Input low **
DIN short circuit to -BAT Input low **