DS-2000 Frequently Asked Questions

When performing tracking analysis, if the number of rotational pulses is set incorrectly, the displayed rotational speed (velocity) will differ from the actual rotational speed. As a result, the order of interest that you intended to analyze will not match the set order. Since the data saved in TRC files (tracking data) and ORF files (DS-0250 data recordings) cannot be modified, when performing tracking analysis again using this data, you will need to set the order of interest that you intended to analyze to match the saved data and then perform the analysis.

As an example, we will explain how to read a TRC or ORF file measured with the setting 20 P/R instead of 30 P/R, and then analyze it with the desired order of analysis being 1st order and the measurement range being 1200 r/min to 3600 r/min.

■ Operating Procedure

Relationship between measured rotational speed and actual rotational speed

The reason why it should be displayed as 1200 r/min but is measured (displayed) as 1800 r/min is due to the following formula.

Therefore, the original measurement range of 1200 r/min to 3600 r/min is displayed as 1800 r/min to 5400 r/min, so we set it to this value.

Conversion of the order of interest

Since the actual rotational speed (velocity) is 20 ÷ 30 times the measured rotational speed (velocity) value, the formula for determining the setting order, taking this into consideration, is as follows.

When the order of interest is 1;

Therefore, set the Line setting in "Tracking Display Settings" to 0.67 ord.

Please note that the rotation speed (velocity) and order displayed on the re-analyzed tracking screen will remain the same as in the original recording.

To perform the correct measurement from incorrect setting data

This shows how to set the upper and lower limits for rotation speed (velocity) in the settings screen of the dialog box accessed from the menu [Input] ⇒ [Tracking Measurement].

This shows the settings screen of the dialog box accessed via [Data Display] ⇒ [Tracking Display Settings] from the menu, with the converted order set to 0.67 (Peak Search on).

Example of measurement data

The X and Y axis orders are displayed using the previous data, so you will need to convert them before reading. Note that the order 0.67 is not included in the resolution, so it is displayed using the most recent order of 0.69.

【supplementary explanation】

Let's consider order 1 in terms of frequency.

Incorrect settings (20P/R)

If the rotational speed (velocity) display incorrectly shows 1200 r/min, the primary frequency will also be measured incorrectly. The primary frequency at 1200 r/min is:

Correct setting (30P/R)

When the display shows 1200 r/min, the correct rotational speed (velocity) is 800 r/min, therefore the primary frequency at 800 r/min is

To see the order 1 that we actually want to measure, we need to look at this order: "13.3 Hz : 20 Hz = x: from the 1st order, x = approximately 0.67th order".