LRF-3000H Handheld Ultrasonic Flowmeter
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must be one that results from actual flow calibration. The scale factor can be entered via M45.
5.5.
4-20mA Current Loop Verification
1
2
3
4
4-20mA +
4-20mA -
4-20mA+
Blue
4-20mA-
Black
The 4~20mA current output connects to the 4-pin din jack on the panel. The color of cable core is blue
（
4-20mA+
）
and black (4-20mA-). With an accuracy of 0.1%, The current output of the Flowmeter
PORTABLE is fully programmable and can be set to various output modes such as 4~20mA or 0~20mA.
Use Window M55 to select the output mode.
The max load of 4-20mA DC
is 750Ω. Exercise care on polarity when connecting.
5.6.
4~20mA Current Loop Output
With a current loop output exceeding an accuracy of 0.1%, the flowmeter is programmable and
configurable with outputs such as 4 ~20mA or 0~20mA selected in menu M55. For details, please refer to
“Window Display Explanations”.
In Window M56, enter a 4mA flow value. Enter the 20mA flow value in Window M57. For example, if the
flow range in a specific pipe is 0~1000m3/h, enter 0 in Window M56 and 1000 in Window M57. If the flow
ranges from -1000~0~2000m3/h, configure the 20~4~20mA output by selecting Window M55 when
flow direction is not an issue. Enter 1000 in Window M56 and 2000 in Window M57. When flow direction
is an issue, an output of 0~4~20mA is available. When the flow direction displays as a negative value, the
current output is in the range of 0~4mA, whereas the 4~20mA is for the positive direction. The output
options are displayed in Window M55. Enter “-1000” in Window M56 and 2000 in Window M57.
Calibrating and testing the current loop is performed in Window M58. Complete the steps as follows:
Press
Menu
5
8
Enter
,move
<
+
or
-
>
to display “0mA”, “4mA”, “8mA”, “16mA”, “20mA” readings,
connect an ammeter to test the current loop output and calculate the difference. Calibrate it if the
difference is not within tolerance. Refer to Section 5.6 for Current Loop Verification.
Check the present current loop output in Window M59 as it changes with change in flow.
5.7.
4-20mA Current Loop Verification
NOTE
Do not perform this operation unless the actual output current value is different from the
value indicated inMenu 58 CL Check Verification. Every meter has been calibrated before
leaving the factory.
Calibrate the anolog input required to expand the hardware debugging menu as below procedures:
Press
Menu
-
>
0
Enter
, enter the password “4213068” then press
Enter
. This action will be inoperative after
powering off.
