A&D AD-4405 Adjustment of the Load Cell Output, Verifying Load Cell Output and Input Sensitivity

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.

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

		E * B * D
Weighing instrument	0.25 £
using one load cell.		A
Weighing instrument	0.25 £	E * B * D
using multi-load cell		A * N

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

Verification Example

	Design:
	Load cell	N=1	5000	* 3 * 0.05
	Rated capacity	A=750 [kg]			= 1 ³ 0.25	. Therefore,
			750
	Rated output	B=3 [mV/V]
			regard the instrument as a good
	Excitation voltage	E=5000 [mV]
			design.
	Weighing interval	D=0.05 [kg]
	Weighing capacity	300 [kg]
3. Installation and Precautions		Page 6			AD-4405 Weighing Indicator