Large Air Gap, Vibration-Tolerant,
GMR Transmission Speed and Direction Sensor IC
A19571
11
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
ASIL Safe State Output Protocol
The xxxxx-A variant contains diagnostic circuitry that will
continuously monitor occurrences of failure defects within the
IC. Refer to Figure 13 for the output protocol of the ASIL safe
state after an internal defect has been detected. Warning faults
will result from faults due to overfrequency conditions from the
input signal. Critical faults will result from hard failures detected
within the A19571 such as a regulator and front end fault.
Note: If a fault exists continuously, the device will stay in perma-
nent safe state. Refer to the A19571 Safety Manual for additional
details on the ASIL Safe State Output Protocol.
Figure 13: Output Protocol of the -xxxBx-A Variant (ASIL Safe State)
N S N
Magnetic
Encoder
I
CC(HIGH )
I
CC(LOW)
I
CC(HIGH )
I
CC(LOW)
S N
I
FAULT
t
w(FAULT,W)
First Direction Output Pulse
Normal
Operation
Warning
Fault
Critical
Fault
Error
I
CC(HIGH )
I
CC(LOW)
I
FAULT
t
w(FAULT,C)
First Direction Pulse Output
Error
