Test method

Exposing the load cell(s) to electrical surges on the mains power lines or on signal, data and control lines

Test conditions

In accordance with 2.7.3.1 Environmental conditions

Preconditioning of load cell

Stabilise load cell under constant environmental conditions

Test level

Level 3

Amplitude (peak value) Power supply lines: (line to line) and (line to earth)

Test load

The test shall be performed with no load or with one small test load ().

Test procedure in brief

This test is only applicable in those cases where, based on typical situations of installation, the risk of a significant influence of surges can be expected. This is especially relevant in cases of outdoor installations and/or indoor installations connected to long signal lines (lines longer than 10 m or those lines partially or fully installed outside the buildings regardless of their length).

This test shall be conducted unless there is justification provided regarding the specific details of the intended use and installation which would render this test unnecessary. The justification for not conducting this test shall be noted in the test report.

The test is applicable to power lines, communication lines (internet, dial up modem, etc.), and other lines for control, data or signal mentioned above (lines to temperature sensors, gas or liquid flow sensors, etc.).

The test consists of exposing the load cell to surges for which the rise time, pulse width, peak values of the output voltage/current on high/low impedance load and minimum time interval between two successive pulses are defined in the referenced standard. The characteristics of the generator shall be adjusted before connecting the load cell.

The test shall be applied to power supply lines, communication lines (internet, dial-up modem, etc.), and other lines for control, data or signal mentioned above (lines to temperature sensors, gas or liquid flow sensors, etc.).

On AC mains supply lines at least 3 positive and 3 negative surges shall be applied synchronously with AC supply voltage in angles 0°, 90°, 180° and 270°. On any other kind of power supply, at least three positive and three negative surges shall be applied.

Notes

Both positive and negative polarity of the surges shall be applied. The duration of the test shall not be less than one minute for each amplitude and polarity.

The injection network on the mains shall contain blocking filters to prevent the surge energy being dissipated in the mains.