Sensing and Internet of Things
9
Installation and Technical Manual for the
Summing In-Line Amplifier, Order Code AA919
ISSUE A
008-0749-00
3.8 | Shunt Calibration
1. An electrical signal equivalent to that produced by a known
load can be obtained by activating the Shunt Calibration
function.
The Shunt Calibration function is achieved by connecting
a high-precision resistor of known value, in parallel (shunt)
with one arm of the strain gage Wheatstone bridge. The
connection is made by a solid-state switch, which will be
activated by the Shunt Cal ON button.
In the Summing In-Line Amplifier, a fixed resistor with re-
sistance of 61900 Ohms is used as the shunt resistor. The
output of the Summing In-Line Amplifier during Shunt Cal
ON depends on the bridge resistance and sensitivity of the
sensor connected to the amplifier.
When a Sensor with the 350 Ohm Bridge resistance and
2.0mV/V sensitivity is connected to the amplifier, the
output of the amplifier will saturate to ~70% of full scale
during the shunt calibration.
Table 3.8a. Shunt calibration Output vs Bridge resis-
tance & Sensitivity
Output of the Summing In-Line Amplifier under shunt
calibration for any other values of the bridge resistance and
sensitivity can be calculated using this equation:
Shunt Cal On Output = (0.000004286* Bridge Resistance) *100
(Sensitivity)
Example:
Consider Sensor with Bridge resistance of 700 Ohm & Sensitivity 10mV/V
Shunt Cal On Output = 0.000004286 * 700*100 = 28.2% of Full Scale = 2.82V
0.010
Figure 3.8a. Shunt Cal ON Option
1. Observe the output.
Figure 3.8b. Shunt Cal ON Output
2. Turn off shunt calibration by clicking the Shunt Cal OFF
button:
Figure 3.8c Shunt Cal OFF Option3.9 | Other Options
3.9 | Disconnect Option
1. To disconnect the device from the PC/laptop, click on the
Disconnect button.
Figure 3.9. Disconnect Option
SL No
Bridge resistance
of Sensor in Ohms
Sensitivity
In mV/V
% of Full Scale Output of
Summing In-Line Amplifier
when Shunt Cal ON
1
350
2
70%
2
350
4
35%
3
350
10
14%
4
700
10
28.2%
