71
Reference Manual
00809-0100-4840, Rev CB
Section 5: Service and Troubleshooting
February 2015
5.5.10
Setting the ambient temperature (on the 3102/3105)
Screen display:
t
Default value:
Auto
The transmitter has an integral temperature sensor to measure the temperature of the air space
surrounding it so that the speed of sound can be correctly computed for sending pulses. The dis-
tance-to-target is then calculated using the formula:
Distance to target = (Speed of Sound in air * Time for echo to return) / 2)
Auto indicates the transmitter is set to continuously measure the temperature using the integral
temperature sensor. It may, occasionally, be necessary to over-ride this automatic monitoring
and fix the temperature to be used in speed-of-sound calculations, for example if the air
temperature is not uniform and the temperature being recorded is not the true air temperature.
Note
This menu option is in the engineering menu “Eng”. See
“Accessing the engineering menu (on
for a map of the menu structure.
To edit and fix the temperature
1.
After entering the “Eng” menu (see the note above), press the green button
repeatedly until “t” is indicated.
2.
Press the blue button
to enter the temperature menu. The display indicates the
present setting.
3.
If this setting is correct, press the red button
and then press the green button
to get
to the next menu option. Otherwise, continue with step (
4.
Press the blue button
to start the editing mode. If the present setting is “Auto”, press
the green button
to change to a three digit number. The first of the three digits
flashes to indicate a number can now be edited.
5.
Press the green button
repeatedly to edit the flashing digit.
(To restore the “Auto” setting, scroll past “9”, press the red button
to save, and then
press the green button
to get to the next menu option).
6.
Press the blue button
to move to the next digit. The digit flashes to indicate it can be
edited.
7.
Repeat steps (
) until the last digit is flashing, and edited as required.
8.
Press the blue button
to confirm the new value. (The flashing stops).
9.
Press the red button
to save the new setting if it is correct, or press the blue button
to not save. Afterwards, depending on the button pressed, either the “t” menu or the
next menu appears.
The next menu is “t.CAL” if using the optional Remote Temperature Sensor to measure the air
temperature. If the Remote Temperature Sensor option is not fitted, the next menu is “Ld.dEF”
(see
“Loading factory default values (on the 3102/3105)” on page 73
Summary of Contents for Rosemount 3101
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Page 68: ...56 Reference Manual 00809 0100 4840 Rev CB Section 4 Starting up February 2015 Starting up ...
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