Emerson Process Management 3400 ユーザーズマニュアル

Reference, Installation, and Operations Manual

Section 6: Meter operation

3-9000-743 Rev S

June 2013

Flow-condition pressure and temperature

207

Data updates

When the Option Board is used, the Daniel Mark III Ultrasonic Gas Flow Meter samples the input
analog signal(s) and updates the corresponding data point(s)
(

LiveFlowPressure, LiveFlowTemperature) once per second regardless of the input selection

(disabled, live, or fixed).

Every five seconds, the meter updates the “in-use” flow-condition pressure and temperature
values (

FlowPressure, AbsFlowPressure, FlowTemperature) depending upon the input

selection, validity of the input data, and the selected data source upon alarm according to

Table 6-6

Table 6-6 Flow-condition pressure and temperature data source

Input Type

(EnablePressureInput or
EnableTemperatureInput)

Data Validity

(

PressureValidity or

TemperatureValidity)

Data Source Upon Alarm

(

FlowPOrTSrcUponAlarm)

“In-Use” Data Source

(

FlowPressure or

FlowTemperature)

Disabled

N/A

“In-Use” value unchanged

Live

Valid

N/A

Average of live values

(

LiveFlowPressure or Live-

FlowTemperature)

Invalid*

Last good value

“In-Use” value unchanged

Fixed

Fixed data point

(SpecFlowPressure or Spec-
FlowTemperature)

Fixed

Valid

N/A

Fixed data point

(SpecFlowPressure or Spec-
FlowTemperature)

Invalid

Last good value

“In-Use” value unchanged

Fixed

Fixed data point

(SpecFlowPressure or Spec-
FlowTemperature)

*Live input can be invalid due to (a) one or more live values is/are at or outside the alarm limits, or (b) the input is being cali-
brated.