Function of the test button of 8mA/16mA electronics
These devices are suitable for use in safety relevant facilities, e.g. for overflow protection and dry run protection.
The electronics continuously monitors via frequency evaluation the following criteria:
. Strong corrosion or damage on the vibrating fork
. Absence of vibration
. Line break in piezo actuator loop
If a malfunction is recognized, the electronics reports this to the signal conditioning instrument via a predefined current. In addition, the connection line to the sensor is monitored for line break and short circuit. The test button in VEGATOR 536, 537 and 636 interrupts the connection line to VEGASWING or VEGAVIB for as long as the button is pressed. After the button is released, a function test is activated in the sensor and the relay in VEGATOR deenergises. Consequently, all downstream applications in the measuring chain are checked. This test with VEGASWING is approved as a recurring test acc. to WHG (Water Resources Act). It is not necessary to start up the sensor or remove it. As an alternative to the test button on VEGATOR, the sensor connection line can be interrupted for a period > 3 seconds, which also initiates the test.
Function of the test button on NAMUR electronics
These devices are suitable for use in safety relevant facilities, e.g. for overflow protection and dry run protection.
The electronics continuously monitors via frequency evaluation the following criteria:
. Strong corrosion or damage on the vibrating fork
. Absence of vibration
. Line break in piezo actuator loop
If a malfunction is recognized or the power supply fails, electronics assumes a defined initial status. The test button interrupts the power supply to the sensor, causing all downstream applications in the measuring chain to be checked on their behaviour in case of line break.
SIL Conformity
The VEGASWING 61/63 and VEGAVIB series 60 fulfil the requirements of function-related safety acc. to IEC 61508/IEC 61511. The accompanying documentation, including key safety data, can be found in the operator's manuals of the respective instruments.
VEGASWING: What has to be kept in mind when installing in pipes?
The vibrating fork should be completely immersed in the product. This means that the fork must protrude at least 40 mm into the tube. In low-viscosity liquids like water, the measurement can be carried out with only 25 mm of immersion.
VEGAVIB: What has to be considered when detecting solid materials in water?
The liquid should have a density of 1 g/cm³. The solid material must be considerably heavier so that it can settle out. Furthermore, no strong turbulence should occur, which might allow solid material to get to the surface again. Solid materials dissolved in the liquid (suspended substances) cannot be detected.
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