Datasheet

MAX31865
RTD-to-Digital Converter
22Maxim Integrated
Table 12. Decoding RTD Faults for 4-Wire Setups When Fault Bit in RTD Data LSB
Register = 1
FAULT
STATUS
BIT SET
DESCRIPTION OF POSSIBLE
CAUSE
CONDITION DETECTED
DESCRIPTION OF
RESULTING DATA
D7
Open RTD element
Measured resistance greater than High Fault
Threshold value
Full scale
RTDIN+ shorted high and not
connected to RTD
Force+ shorted high and
connected to RTD
D6
RTDIN+ shorted to RTDIN-
Measured resistance less than Low Fault Threshold
value
Near zero
RTDIN+ shorted low and not
connected to RTD
RTDIN- shorted high and not
connected to RTD
Force+ shorted low
D5
Open RTD element
V
REFIN
- > 0.85 x V
BIAS
Full scale
Force+ shorted high and
connected to RTD
Force- unconnected
Indeterminate
Force+ unconnected
Force+ shorted high and not
connected to RTD
Force- shorted high and not
connected to RTD
Force- shorted high and connected
to RTD
Force- shorted low and not
connected to RTD
D4
Force- shorted low and connected
to RTD
V
REFIN
- < 0.85 x V
BIAS
(FORCE- open)
Indeterminate
RTDIN- shorted low and connected
to RTD
Appear to be valid
D3
Force+ shorted low
V
RTDIN
- < 0.85 x V
BIAS
(FORCE- open)
Near zero
RTDIN+ shorted low and
connected to RTD
RTDIN- shorted low and connected
to RTD
Appear to be valid
RTDIN- shorted low and not
connected to RTD
Force- shorted low
D2 Overvoltage or undervoltage fault Any protected input voltage >V
DD
or < GND1 Indeterminate