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Reference Manual

00809-0100-4811, Rev DA

Section 6: Service and Troubleshooting

January 2015

Service and Troubleshooting

6.2.5 Interface measurements with fully immersed probes

The Rosemount 3300 Series has a measurement option which makes it possible to handle

interface measurements when the product level is not visible, for example in a full bridle pipe as

illustrated in Figure 6-6. In this case, the probe is fully immersed into the upper product, and

only the interface level is detected by the transmitter. Even if the upper product level drops, it is

ignored by the transmitter which continues to measure only the interface level, but the

measurement accuracy is reduced since the transmitter does not take into account the

influence of the air gap above the product surface.

The Measurement Mode parameter is available via the HART command [1, 3, 3, 4]. Select the

Interface when Immersed Probe option.

Measurement mode Interface when Immersed Probe can also be activated in the RCT software:

1. Open the Setup window.

2. Select the Environment tab.

3. Select Measurement Mode Interface when Immersed Probe.

4. Select the Send Page button.

Note

Do not use Measurement Mode Interface when Immersed Probe in “standard” applications when

both interface level and product level are measured.

If the product level drops, the air filled region in the upper part of the pipe will slightly reduce

the measurement accuracy of the interface level. To achieve high accuracy in this measurement

mode the probe must be fully immersed.

Figure 6-6. Interface Level Measurements in a Full Bridle Pipe

Note

Adjust Threshold T2 if the level pulse is not detected.

Interface distance

Interface level

Product level

is ignored

Interface level is

measured

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