FAILSAFE PARAMETERS (P070 to P072)
As preset, in the event of a measurement or technical difficulty, the XPL+ holds the Reading, Bar Graph,
SAM-20 relays (if used) and AO-10 mA outputs (if used), at their last "known" values.
To operate process control equipment under these conditions, alter the following parameters as required.
If alternate Failsafe Operation is not required, proceed to RELAY PARAMETERS.
P070 FAILSAFE TIMER
Enter the time to elapse (in minutes), upon a difficulty, before failsafe operation is activated.
In the RUN mode, when a difficulty first occurs, the Reading, Bar Graph, relay status, and mA
outputs are held at "last known" values and the Failsafe Timer is activated.
When a valid measurement is made before the timer expires, the XPL+ advances to the "new"
material level (if changed) as
normal
(per Measurement Response, P003) and the timer resets.
If the timer expires (before a valid measurement is made), the XPL+ advances to the Failsafe
Material Level (P071) as restricted by Failsafe Advance (P072).
When a valid measurement is made after the timer expires, the XPL+ advances to the "new"
material level (if changed), as restricted by Failsafe Advance (P072) and the timer resets.
If the timer expires due to a measurement difficulty, "LOE" flashes in the Reading display.
Technical difficulty messages flash in the Reading display before the timer expires. The
offending terminal connections are displayed in the Auxiliary Reading display.
DISPLAY CAUSE
"LOE" weak echo (see TROUBLESHOOTING GUIDE Measurement Difficulties).
"Short" short circuited transducer cable, or defective transducer
"OPEn" open circuited transducer cable, or Point Number is scanned but a transducer
is not connected, or defective transducer
"Error" reversed Ultrasonic/Temperature transducer terminal connections or wrong
Transducer (P004) entered.
While a short duration Failsafe Timer value may be required
(when process control equipment is used) avoid entering
a value so short as to cause nuisance activation.
This feature is automatically altered when Measurement Response (P003) is altered.
values: 0.000 to 9999
TROUBLESHOOTING GUIDE
APPLICATIONS PARAMETERS
PL-532 37
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