Span Test; Sensing Head Level Test - Siemens SITRANS WFS320 Operating Instructions Manual

Sensing heads

Table of Contents

6.3

Span test

1. Gently push the sensing head moving beam to the right. The LVDT output should steadily

increase until a level of 0.75 to 1.0 V AC is achieved.

2. Gently push the sensing head moving beam to the left. The LVDT output should steadily

decrease until zero is reached and then start increasing again to 0.015 to 0.5 V AC.

3. Ensure the LVDT output always returns to 0.10 ± 0.05 V AC, (to the right hand side of zero)

when pressure on the moving beam is released.

Note

The LVDT core must not contact the inside of the LVDT over the range of core travel. The

actual LVDT core travel during this procedure is less than 3 mm (1/8").

6.4

1. With the voltmeter still connected to the LVDT output, hang the test weight directly off the

sensing plate.

2. Check to ensure that the LVDT output does not change by more than 0.01 V AC.

Note

If the change is greater than 0.01 V AC:

1. Adjust the sensing head level, [refer to Sensing head (Page 13) ] until the change with

2. Remove the test weight and readjust the LVDT Output Zero, if necessary. If the level

SITRANS WFS320

Operating Instructions, 02/2016, A5E32880290-AB

and without the test weight on the sensing plate is less than 0.01 V AC.

test is performed after the integrator has been calibrated, a new integrator zero and

span calibration, span adjust, and factoring, should be performed.

Commissioning

6.3 Span test

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