Ref: REFLEX/SCANFLEX MANUAL
EDITION 1: JULY ’97 46
D) No output:-
1. Disconnect the external wiring and check outputs with a meter. The expected
output is displayed at Pr.34 for each point of measurement. If OK, the fault is
external; if not OK, the module is faulty.
E) Maximum output less than 20mA:-
1. The external load may be too high. Specification is 750 Ohms at 20mA.
F) The output does not match the application:-
1. Check that the correct span is programmed at Pr.5 and that the correct option
has been selected at Pr.30.
G) Output is unstable:-
1. It should be as stable as the display, from which it is calculated. To test,
disconnect external wiring and check with a meter.
OPERATIONAL FAULTS
A) Display stays high:-
1. Check for obstructions close-in to the transducer.
2. If standpipe-mounted, refer to Page 47.
3. Ensure that the isolation kit is fitted to the transducer, refer to Pages 50-52.
(Not applicable if the transducer has an integral flange).
4. Check that the rate of change (Pr.7) is high enough for the application.
5. Check the entry at Pr.6. This should not be less than the factory default.
B) Display is lower than expected:-
1. Check that Pr.4 & 5 are correct for the application.
2. It can be caused when the level rises into the blanking zone (Pr.6). The system
may lock-up on a multiple echo and track this when the level falls. The
correct reading can be re-established by pressing 'MODE-1-MODE' but to
effect a permanent cure, the transducer should be raised to prevent the level
encroaching into blanking.
3. It can also be caused by poor surface quality. On liquid applications this may
be foam or turbulence and on solids, a very irregular surface.
4. The level may be moving at a faster rate than that programmed in Pr.7. The
rate of change value should be increased to match the true rate.
C) Display changes in steps:-
1. Increase rate of change at Pr.7 to match the true rate.
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