Burster 8402 Technical Product Information/Start-Up, Operation, Installation Instructions

Technical Product Information
Start-up, Operation, Installation Instructions Type 8402
Miniature Load Cell Type 8402

1. Introduction

The load cells of the series Type 8402 are primarily designed for force measurements in the unit N in conjunction with
manufacturing facilities.
When determining masses it is important to take the local acceleration of free fall (g ≈ 9.81 m/s
2
) into consideration.

2. Preparation for operation

2.1 Unpacking

Carefully check the sensor for damage. Should transport damage be suspected, please notify the supplier within
72 hours. The packaging must be kept for inspection by the manufacturer's representative and/or the supplier.
Transportation of the Type 8402 may only be performed in the original or equivalent packaging.

2.2 Start-up

The load cell is connected exclusively to measurement amplifiers equipped with a safety transformer as specified
according to VDE 0551. Even the transmitter and devices connected downstream, which are electrically connected to
the sensor's signal lines, must be equipped with a safety transformer according to VDE 0551.

2.3 Grounding and isolating

All lines are isolated from the housing, however the maximum permissible voltage is 30 V. The cable shielding is not
connected on the sensor-side.

2.4 Storage

The sensor must be dry stored at 0 ... 60 °C. Dampness is not permitted. Special measures need not to be taken for
commissioning after storage.

3. Operating principle

A load cell consists of a spring element which is deformed by the applied force being measured and a device which
measures this deformation.

3.1 Spring element

The spring element constitutes the most important mechanical component of the load cell. It is designed to absorb the
load being measured and to transfer it to an area of homogenous extension. Here the elastic properties of the spring
materials are used to indirectly determine the load. In addition to these elastic properties the materials used in load cells
must also meet other conditions with the result that only a few selected materials come into question for high-quality
sensors. burster goes one step further and primarily uses aviational materials instead of DIN-approved materials, as
these have additional quality requirements.
In the Type 8402 the spring is designed as a hollow compressible body (Fig. 1). Here the force being applied influences
the height of the spring - compressing it. This simultaneously increases its diameter. These deformations are so slight
that they are invisible. Characteristic here is the small body in relation to the nominal load which in conjunction with the
high spring rate ensures a high resonance frequency and thus permits rapid measurement.
Elongation or strain measurement:
The elongation of the spring's surface is measured using strain-gauges, see Fig. 2. The gauges are attached to the
spring of the load cell making them subject to the same deformation as the spring. As such the elongation and therewith
the force can be measured electrically. In the Type 8402 the strain gauges are attached to the inner side of the spring
element.
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. .
http://www.burster.com . e-mail: info@burster.de