Diagnostics
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the data points. The “Travel Set Point” and “Travel” columns identify travel data in percent of ranged travel. The “Drive” column identifies the drive signal in percent of maximum drive. The “Actuator Pressure” column identifies actuator pressure in psi, bar, or kPa, depending upon the units stored in the instrument. Click the Write to File button to save the data to a file as tab-delimited ASCII text. You can use this data with a spreadsheet such as Microsoft Excel.
15.3.2.3
Analyzed Page The ValveLink software analyzes the information collected from the Total Scan test and displays the analyzed data on this page. For sliding-stem valves, the software calculates and displays friction, spring rate, bench set, and seat load data. For rotary valves, the ValveLink software calculates and displays torque, spring rate, and bench set data. The following define the fields on the Analyzed page. The units of measure used in this test depend on options selected through the Preferences selection on the Customize ValveLink menu.
15.3.2.3.1
Sliding-Stem Valves, Analyzed Data Zero Ranged Travel at—Travel set point, in percent, that corresponds with a ranged travel of zero. ValveLink establishes a best fit line through the Dynamic Error Band data and projects this to a ranged travel of zero. ValveLink converts the X axis point where the ranged travel is zero from input percent. Full Ranged Travel at—Travel set point, in percent, that corresponds with the point where ranged travel is maximum, that is, the point where the travel no longer increases with an increase in travel set point (or decrease in set point when Zero Control Signal = Open). Average Dynamic Error—The calculated average difference between the opening and closing curves based upon an analysis of the dynamic error curve from 5% travel to 95% travel. Maximum Dynamic Error—The calculated maximum difference between the opening and closing curves based upon an analysis of the dynamic error curve from 5% travel to 95% travel.
July 2000
VL2000 Series