Omega Engineering ULTRASONIC LEVEL TRANSMITTER LVU-90 - Manual (Page 5)

Step Six Step Seven
CALIBRATION CALIBRATION
The LVCN-90 is factory calibrated with a fixed measurement span of
6 feet. The 4 mA position is located 72" from the transducer face. The
20 mA position is located 3.6 inches from the transducer face. Refer
to the current to distance and distance to current conversion charts in
step seven for reading the current output.
1. Connect a multimeter in series to read the current output.
2. Verify that as the distance from the liquid to the LVCN-90
increases, the current signal decreases.
3. Verify that as the distance from the liquid to the LVCN-90
decreases, the current signal increases.
Current to Distance Conversion Chart (Nominal)
Distance to Current Conversion Chart (Nominal)
LED Indication
The LVCN-90 features a single LED indicator which is used for
power and fail-safe indication. During normal operation, the LED
will be ON continuously to indicate that the transmitter has power and
a strong echo signal return strength. Should the LED begin to
FLASH, it indicates that the transmitter has no signal return strength
and the device has gone into a fail-safe condition. During the fail-safe
condition, the current will increase up to 22 mA and hold until the
acoustic signal is reacquired. Once reacquired, the LED will turn back
ON continuously and the current will indicate the appropriate mea-
sured value.
com
mA
(+)
4
5
6
Power
Supply
Power
Supply
com
mA
(+)
19
20
21
3.6"
72"
20 mA
4 mA
3 . 6
0 6
1 2
1 8
2 4
2 0 . 0
1 9 . 4
1 8 . 0
1 6 . 6
1 5 . 2
3 0
3 6
4 2
4 8
5 4
1 3 . 8
1 2 . 4
11 . 0
0 9 . 6
0 8 . 2
6 0
6 6
7 2
0 6 . 8
0 5 . 4
0 4 . 0
Current
mA
Distance
inches
Current
mA
Distance
inches
Current
mA
Distance
inches
2 0
1 9
1 8
1 7
1 6
1 5
0 3 . 6
0 7 . 9
1 2 . 1
1 6 . 4
2 0 . 7
2 5 . 0
1 4
1 3
1 2
11
1 0
0 9
2 9 . 2
3 3 . 5
3 7 . 8
4 2 . 1
4 6 . 3
5 0 . 6
0 8
0 7
0 6
0 5
0 4
5 4 . 9
5 9 . 2
6 3 . 5
6 7 . 7
7 2 . 0
Current
mA
Distance
inches
Current
mA
Distance
inches
Current
mA
Distance
inches
3.6"
72"
4 mA
20 mA
68.4"
POWER
4-20 mA
(-) (+)
GND 12-36 VDC
LED