FAD-40 Technical Manual, Rev.2.1.0; February 2022
Page 9 of 55
The quality of the instrument’s ground will determine the accuracy and the safety of your measuring system. A
proper ground connection is needed to minimize extraneous electrical noise effects on the measurement. A
poor ground can result in an unsafe and unstable operation. It is important that the instrument should not share
power lines with noise-generating equipment such as heavy load switching, motor control equipment, inductive
loads, etc. If the condition of the power line in the plant is poor, prepare a special power line and grounding.
Before interfering the instrument, turn off the power and wait at least for 30 seconds.
3.2.2. Load Cell Connection
To avoid damages, the load cell wiring should be made carefully before energizing the instrument. Load cell
connection details are shown below in figure 4.2. In 4-wire installations the sense and excitation pins with the
same polarity should be short circuited at the connector side. If you have a junction box in your system, use a 6
wire cable between FAD-40 and the junction box, and short circuit these pins at junction box for better
performance.
Load Cell
Connector
4 wire LC connection
6 wire LC connection
WARNING:
Connect the load cell cable shield to the reference ground or the
shield pin of the load cell connector.
Figure 4.2
– Load cell connection
When you use a junction box and one or more load cells with 4 wires you have to short-circuit the excitation
(Exc) and sense wires (Sen) the same polarity as show on the figure 4.21.
Junction box
6 Wire-cable
FT-10 Indicator
Bridges
4W-Load cell
Shield
Shield
+ Exc
+ Sig
- Sig
- Exc
Shield
Figure 4.21
– 4 wires load cell connection via connection box
