Emerson Rosemount 3101, Reference Manual

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Reference Manual
00809-0100-4840, Rev CB
Section 4: Starting up
February 2015
Starting up
4.3.2 First measurements (on the 3101)
With the transmitter installed and display units selected, the display will show what the
instrument calculates as the liquid depth (level). This value is calculated by the microprocessor
as being the difference between the distance-to-target being measured and the default value
for the datum or bottom reference (b.rEF).
Figure 4-2. Transmitter Bottom Reference
A. Transmitter Bottom Reference
B. Distance-to-target
C. Depth (Level)
Before changing any of the default values, press the blue button

to change the PV display to
indicate distance-to-target, as measured by the transmitter from the transmitter face.
This value is shown alternately with the text “diSt” to indicate the display is in distance mode.
The calculation can be checked against a manual measurement if required.
Note
A useful feature at this stage is that the transmitter can be used as an electronic tape measure.
With an empty tank or vessel, the transmitter will read the distance to the bottom of the tank.
This distance can be noted and later used when setting b.rEF.
Press the blue button

again to get to the echo size. This is a scale of 0 to 100. (It is possible to
record a value greater than 100). With the display in this mode, the central “:” cursor will flash
once for every echo received, which under normal circumstances will be once per second.
Note
It is useful at this point to check that the maximum echo size available is being received.
Adjust the position of the instrument until the highest echo size is continually shown.
In most applications, the signal strength will vary over a wide range: 20 to 80.
Press the blue button

again to return to the original level reading and start the set-up routine,
beginning with setting the bottom reference of the transmitter.
Note
The output of the transmitter will vary during programming, as the various default values are
changed. The display will automatically revert to the level reading from any other display after a
period of four minutes.
B
C
A