Formax 6204 Series, Руководство по обслуживанию

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OMR code test
Use this menu to test the OMR reading head (RH1) and, if necessary, to readjust the relevant OMR electronics.
1. Select “Adjust” to start testing the reading head.
The settings of the current job are used for this test. This implies that an OMR job must be selected, otherwise
the text “Select a job with OMR” will appear. If the OMR codes on the paper used differ from the OMR codes for
the current job, the number of marks that have been read are incorrect.
After selecting “Adjust”, another menu appears. Information about the number of OMR test sheets to be placed
in the upper feeder is first shown.
2. Select “Start adjust” to start the OMR adjustment. The text “Adjusting…” appears.
The end result will either be:
- “Adjusting OK”
- “Adjusting FAILED”
If readjustment of the OMR electronics was successful, “Save and exit” is displayed.
3. Select “Save and exit” to return to the original OMR menu. This menu now shows the benefit of readjusting the
OMR electronics.
Select the “Test” key to show:
• Mark quality (the quality of the marks: bad, good or very good)
The mark quality is either:
Bad: Mark amplitude < 0.6 V
Good: Mark amplitude between 0.6 V and 1.5 V
Very good: Mark amplitude higher than 1.5 V
• Marks (the number of marks that have been read)
• Gain (the gain of the amplifiers involved in the OMR electronics, the values are 1, 3, 5 or 7)
• Vp-p: peak to peak voltage
Select the “OMR info” key to display the information screen. This screen shows additional OMRrelated information.
This information is based on the last read document and the job settings (OMR code type etc.). The displayed
information is what is interpreted from the read OMR code.
Select “Show OMR” to display a graphical representation of the marks that had been read (oscilloscope function).
The information shown is derived from the most recently read document.
The information screen shows the time-dependant OMR output voltage and the reading window. See following
figure.
The start of the window is represented by a vertical line, the end of the reading window is also represented by a
vertical line. In between the marks should be given where the position of the marks related to the window position
is also giving some information, i.e. when the first mark is very close to the opening of the window; this could mean
that the window position is programmed wrong.
The upper horizontal dotted line represents the noise level, i.e. the white level. The lower horizontal dotted line
represents the level below which a mark (i.e. detection level) has been detected. The detection level is determined
when the adjustment procedure is performed. The detection level is 60% of the top level. A mark is detected as an
OMR-mark when more than 5 digital samples consecutively are below the detection level.
The numbers 1 through 6 indicate where a mark is expected. The distance between the numbers is exactly the
same as the programmed line spacing. Select the arrows to scroll to the left or the right. Scrolling to the right shows
a later point in time; scrolling to the left shows an earlier situation.
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063.1
Service
Guide
39