Motor Torque PM Procedure

Background

Measuring the torque required to move various ESI stages has proven to be a useful diagnostic for monitoring instrument performance. Motor torque should generally be below 3 at all positions if the stage is healthy. This document describes the steps required for technical staff to measure ESI motor torques.

Data Acquisition

  1. Setup. Verify that ESI is cabled up and powered on, and that summit personnel are clear of the instrument. Bring up an xterm window on esiserver as user esieng.
  2. Execute scripts. Run the following commands to gather the data:
    	~esieng/bin/motor-torque-test imflt
    	~esieng/bin/motor-torque-test ldflt
    	~esieng/bin/motor-torque-test prism
    This will general logfiles (containing raw motor positions and corresponding torque measurements in CSV format) in the ~esieng/log directory. Here is the typical terminal output:
    [175] esieng@kanaha: ~esieng/bin/motor-torque-test imflt
    setting imfltnam = in (wait)
    [1] 26520
    setting imfltnam = out (wait)
    setting imfltnam = in (wait)
    could not open /dev/kbd to get keyboard type US keyboard assumed
    could not get keyboard type US keyboard assumed
    [1]  + Terminated             cshow -s esi -timestamp imflttor imfltraw > $datafile
    could not open /dev/kbd to get keyboard type US keyboard assumed
    could not get keyboard type US keyboard assumed
    logfile = ~/log/motor-torque-test.imflt.2010_01_12_11h39m.log

Data Analysis

  1. Generate Plots. Create Excel spreadsheet. Read the CSV data from corresponding logfiles into Excel spreadsheets and plot motor torque (2nd column) vs. raw position (1st column). Here's a sample spreadsheet which can be used as a template.

Sample output

Here are resulting plots from testing performed on 2010-Jan-12.

Imaging Flat

Plot of IMFLTTOR vs. IMFLTRAW

Low-Dispersion Flat

Plot of LDFLTTOR vs. LDFLTRAW

Prism

Plot of PRISMTOR vs. PRISMRAW

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