Adjustment Of The Load Cell Output; Verifying Load Cell Output And Input Sensitivity - A&D AD-4405 Instruction Manual

3.1.3.

Adjustment of the Load Cell Output

Caution Use a metal film resistor in the range of 50kohm to 500kohm with a
good temperature coefficient, when adding a resistor to adjust a load
cell output. Use as large of a resistance value as possible in the range
in which the zero adjustment is possible. Solder this resistor at a point
near the load cell or the indicator.
In Case of Reducing the Output Voltage
When the zero output is too large, add a resistor
between EXC+ and SIG-.
In Case of Adding an Offset Voltage to the Output
When the zero output is too small, add a resistor
between EXC+ and SIG+.
3.1.4.

Verifying Load Cell Output and Input Sensitivity

The input sensitivity of the indicator is 0.25mV /division or more. Adapt to the following
inequality, when you design a weighing instrument using the indicator and load
cell(s).
Caution A change in input voltage sensitivity is required to cause a one division
change of the display. Select as large an input sensitivity voltage as
possible so that the weighing interval becomes stable.
Consider the leverage if a lever is used.
Weighing instrument
using one load cell.
Weighing instrument
using multi-load cell
Verification Example
Design:
Load cell
Rated capacity
Rated output
Excitation voltage
Weighing interval
Weighing capacity
3. Installation and Precautions
E B D
* *
. 0 25 £
A
E B D
* *
. 0 25 £
A N
*
N=1
A=750 [kg]
B=3 [mV/V]
E=5000 [mV]
D=0.05 [kg]
300 [kg]
Page 6
A: Rated capacity of load cell [kg]
B: Rated output [mV/V]
D: Weighing interval [kg]
E: Excitation voltage [mV]
N: Number of load cells
5000 3 . 0 05
* *
= 1 ³
750
regard the instrument as a good
design.
AD-4405 Weighing Indicator
. 0 25
. Therefore,