Section 1
Ref: REFLEX/SCANFLEX MANUAL
EDITION 1: JULY ’97 39
4. Is the target within the empty distance specified at Pr.4? This is particularly
important if the temperature varies and no compensation is applied.
5. Is the vessel empty, with a conical parabolic or spherical bottom? If the
transducer is not central the transmission pulse may be reflected from the
the sloping sides and not back to the transducer. Under these conditions the
display will show 'LOSS OF ECHO' but the failsafe designation will operate
until product returns and the system will automatically recover and track the
level. If the transducer cannot be mounted centrally, the problem may be
overcome by the installation of a 'target' plate.
6. Connect a known good transducer. If this operates, check the gain value by
pressing the 'TEST' key. The percentage displayed ranges from 0-100, the
lower the figure the better the signal strength. If the gain is 50-100, check the
surface on liquid applications for foam or floating debris, which may cause
poor echoes.
7. Check that the ST6 eprom is seated correctly at U6 on the bottom PCB.
E) The keypad fails to operate:-
1. Check the alignment of the plug with the top PCB connectors.
2. Check that the key press sequence is valid, refer to Programming Section.
3. Power-down and wait 5 secs. Power-up and press 'MODE'. This should
result in 'PROG' being displayed. It is now advisable to reset the unit - refer
to Page 16.
F) Analogue output is unstable:-
1. Connect test meter in series with your external wiring.
Can fault be seen on test meter? If yes, then use Pr.34 to enter a stable value
into the current loop. Suitable values range from 4 to 20. If output is still
unstable disconnect external wiring and connect meter across terminals 25 and
26 and repeat Pr.34 test. If still unstable, contact Hycontrol. If stable, check
wiring and meters etc.
G) Analogue has no output:-
1. Check programme value at Pr.30 - Value 1-6
2. Insert test meter in series with the output. Under Pr.34 enter a fixed output.
If still no output, then connect test meter directly across terminals 25 and 26,
repeat test under Pr.34. If no value is read at terminals 25 to 26 contact
Hycontrol.
H) Analogue output is less than 20 at maximum display reading:-
1. The load attached to the output may be too high. To check this disconnect all
the external wiring and see if it now reads 20. The output is capable of driving
20mA into 750 Ohms.
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