Emerson 3051S Specifikace stáhnout pdf (Strana 95)

Reference Manual

00809-0200-4801, Rev CA

July 2010

6-17

Rosemount 3051S

Figure 6-15. Trend of Standard

Deviation in DeltaV Process

History View

Finally, when the SPM data is trended in DeltaV, it is possible to configure HI

and/or LO alarms on the mean or standard deviation via the AI Block. This

can be done by right-clicking on the AI Function Block in Control Studio, and

selecting the option “Assign Alarm”. The Block Alarm configuration window

will let you set up desired alarm limits. Refer to the DeltaV Books Online for

detailed information on configuring alarms.

PLUGGED IMPULSE

LINE DETECTION

TECHNOLOGY

Introduction Pressure transmitters are used in pressure, level, and flow measurement

applications. Regardless of application, the transmitter is rarely connected

directly to the pipe or vessel. Small diameter tubes or pipes commonly called

impulse lines are used to transmit the pressure signal from the process to the

transmitter. In some applications, these impulse lines can become plugged

with solids or frozen fluid in cold environments, effectively blocking the

pressure signals (Figure 6-16). The user typically does not know that the

blockage has occurred. Because the pressure at the time of the plug is

trapped, the transmitter may continue to provide the same signal as before

the plug. Only after the actual process changes and the pressure transmitter’s

output remains the same may someone recognize that plugging has

occurred. This is a typical problem for pressure measurement, and users

recognize the need for a plugged impulse line diagnostic for this condition.

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Emerson 3051S Specifikace Strana 95