Page 28
MiniRanger Plus – INSTRUCTION MANUAL
7ML19981CJ02
In applications where the zero level is above the bottom of the vessel and it is desired to
monitor the zone below the normal zero, range extension (P801) can be used to extend
the range into the far end blanking. Range extension is entered as a percent of P006. As
range extension reduces the protection afforded by the far end blanking, it should be
used judiciously. Avoid excessive range extension as this can reduce the measurement's
reliability and accuracy. Range extension is factory set for 20% of P006. If it is found that
false echoes are appearing ahead of the blanking zone, P006 should be reduced
accordingly.
Blanking is automatically corrected for sound velocity change where temperature and
velocity compensation are used; keeping the blanking at the distance at which it is set.
Loss of Echo
A loss of echo occurs when the MiniRanger Plus deems that the calculated
measurement is unreliable, i.e. the echo confidence (P805) is less than the threshold
(P804). This can be due to such circumstances as high level of electrical noise, poor
grounding, or poor transducer aiming. Refer to Troubleshooting. If the condition persists
for a time beyond the limit as set by the fail-safe timer (P070), the confidence icon
changes from full to partial and the reading and mA output are forced to the fail-save
default (P071) at the response rate (P003).
Upon receiving a reliable echo, the loss of echo condition is aborted (icon returns to full)
and the reading, mA, and relay output return to the present level at the response rate.
Relay operation responds, as programmed, to the default level as an actual material
reading.
