Vega MINITRAC 31 4 … 20 mA_HART - four-wire Bedienungsanleitung PDF herunterladen (Seite 42)

6 Set up with the display and adjustment module

MINITRAC 31 • 4 … 20 mA/HART - four-wire

40447-EN-131119

Inthismenuitemyoucandenethecharacteristicsofthesensorand

its behaviour in case of a fault.

Inthismenuitemyoucandenethebehaviourofthecurrentoutput.

You can specify the current at minimum and maximum density sepa-

rately.

Radiationfromexternalsourcescaninuencethemeasuringresultof

the sensor.

Possible external radiation sources can be, for example, a weld joint

test on a neighbouring facility or other radiation-based instruments.

An X-ray alarm is triggered if the impulses (ct/s) are more than 25 %

abovethemax.valuefromthelinearizationtable.

This fault message is only outputted for the period of the increased

X-ray radiation. Then the fault message is automatically reset.

In this menu item you can determine the behaviour of the sensor

when external radiation sources appear.

You can choose whether the sensor should output modulated current

(dithering) or the set fault current in case external radiation appears.

In the case of modulated measuring current (dithering), the last

valid current value is maintained and the current output modulates a

square-wave voltage ±1 mA around this value.

In this menu item you can activate the relay output and determine its

function as well as the switching points.

When the output of the process values is set, you can choose be-

tweenoverllanddryrunprotection.

The relay outputs of the sensor react accordingly.

The following reference values can be selected:

•

None - Relay operates as fail safe relay

•

Electronics temperature

Setup/Current output

mode

Setup/Current output

Min./Max.

Setup/External radiation

alarm

Setup/Relay

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Vega MINITRAC 31 4 … 20 mA_HART - four-wire Bedienungsanleitung Seite 42