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Setting up an Optical Mark Reader

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Setting up an Optical Mark Reader

There are numerous options available for configuring your OMR but once it has been correctly set up and is working properly, it is unlikely that any settings will need to be adjusted until a new delivery of OMR sheets is received.

To adjust the OMR settings, select Tools | Setups | OMR to display the OMR Setup form which consists of three pages.

      1. OMR Printing Page

The adjustments available on this page should only be applied after printing and reviewing a test sheet, which is generated by clicking the Print Test Sheet button. The resulting test sheet enables you to take measurements, which you can enter in this page to ensure the accuracy of printing OMR sheets.

The following adjustments are available:

        1. Printer Offset

The printer offset determines the distance from the edge of the paper to the printer boundary. The printed test sheet displays arrows enabling the distance from the top and the right of the test sheet to be measured. Once measured, these values should be entered in the Top Test Sheet Measurement and Right Test Sheet Measurement fields accordingly. Alternatively, the sliders can be used to select the required values.

Once these values have been entered, no further adjustment should be needed until a new delivery of OMR sheets is received or unless the current printer is changed.

        1. Scaling

A vertical arrow is displayed on the OMR test sheet. The length of this arrow should be measured and the value entered in the Scale Length field. Alternatively, the slider can be used to select the required value.
        1. Print Sheet Number

The sheet numbers for the different types of OMR sheet are all in the same series of numbers. For example, if you print six registration sheets numbered 1 to 6, then three Absence sheets, the Absence sheets are numbered 7 to 9. If you then print four more registration sheets, they are numbered 10 to 13, and so on.

There are three ways in which the sheet number may be recorded. Select one of the following radio buttons according to your requirements.

  • As Barcode – if barcode printing is enabled, the sheet number is printed as a barcode alongside the sheet number box.

  • As Dashes – if this option is selected, the sheet number is represented by dashes in the sheet number box. Please note that when a test sheet is printed the dashes are not part of the test and should therefore be ignored.

  • Print Nothing – select this option if you wish to enter sheet numbers manually.
      1. OMR Port Settings Page

A majority of the settings on this page are automatically set and should not require adjustment unless you are experiencing problems connecting to the OMR.

If you need to make any adjustments to these settings, do so in the following order:

  1. Change the settings as appropriate (i.e. baud rate, parity etc.).

  2. Click the Apply button to confirm the settings.

  3. Switch the OMR off and on again. This discards any previous initialisation and resets the OMR.

  4. Wait for the OMR to ‘beep’ and the light to change from green to red.

  5. Click the Test OMR Port button and wait several seconds until the report or message is displayed.

  6. Click the OK button to save the new parameter(s). You may wish to move to another tab to check more parameters before clicking the OK button.

        1. Port

There are likely to be two or more ports available. Your choice of port will depend on the type of connector the OMR has, together with any other devices that may be using that port.
        1. Parity

As data is sent checks are made that the data being sent from the OMR is the same as that being received by the computer. This setting should only be changed on direct advice from your OMR supplier or Capita ES support.
        1. Data Bits

Refers to the number of bits per character. This setting should only be changed on direct advice from your OMR supplier or Capita SIMS support.
        1. Stop Bits

Refers to the number of bits sent to denote the end of a character. This setting should only be changed on direct advice from your OMR supplier or Capita SIMS support.
        1. Baud Rate

This is a measure of the rate at which data is sent from the OMR to the computer. Select the required value from the drop-down list. In most circumstances, the setting should be left at 19200.

If you experience problems connecting to the OMR or persistent read problems, try resetting the value to 9600 for Windows NT® or 1200/2400 for Windows® 2000, noting that the OMR must be switched off and then on again to initialise the new setting.

        1. Test OMR Port Button

Make sure that the OMR is switched on, then click this button to attempt communication with the OMR. A message will appear advising if the communication has been successful. If the connection has failed, try reducing the baud rate, then retesting the connection, noting that the OMR must be switched off and then on again to initialise the new setting. If this does not resolve the problem, switch off the OMR, reboot the machine, then switch the OMR on and try again.
      1. OMR Reading Page

This page shows the Discrimination and Sensitivity settings, which determine how the OMR should interpret different marks on OMR sheets. They are used to distinguish a genuine mark from an erased mark, partial mark or dirt/crease on an OMR sheet.

The OMR measures the size, darkness and sharpness of marks on the OMR sheets and combines these to produce a single mark density value (score) for each read area. These scores range from 0 - 15 where 0 represents no mark and 15 represents a very good mark.

The Sensitivity setting determines the minimum threshold score that the OMR will recognise as a clear mark and therefore defines how leniently or strictly the software will interpret marks. The mark on the OMR sheet must produce a score greater than 5 in order for it to be accepted.

  • If you are experiencing problems reading faint lines on an OMR sheet - reduce the Sensitivity setting.

  • If you have OMR sheets that are crumpled or dirty, it is worth increasing the Sensitivity setting, perhaps to 8, to make sure that only clear, dark lines are recognised as valid.

The Discrimination setting is used to set the minimum difference between the densities of competing marks. The setting is set by default to 5. Lowering the discrimination forces the OMR to discriminate between marks that are very similar. This reduces the number of multiple mark errors, but risks the OMR making arbitrary decisions. Increasing this value reduces the scope of discrimination, except where the difference between the marks is obvious. This reduces the risk of marks being incorrectly discriminated, but increases multiple mark errors.

NOTE: If you are experiencing a high number of multiple mark errors, reduce the Discrimination setting.


Both Sensitivity and Discrimination fields are set to 5.

Two marks are read that are above the sensitivity setting with scores of 10 and 7 and therefore pass the minimum threshold of 5. The difference between these scores is 3 which is lower than the discrimination setting of 5 and both marks are accepted. A multiple marks error may be produced.

Two marks are read with sensitivity values of 10 and 4, so only one of them passes the minimum sensitivity threshold of 5. The difference between these two values is 6 which is above the discrimination setting of 5, so the mark with the highest score is accepted.

      1. Unable to Handshake with OMR

When the OMR Core Component dialog is opened via Focus | Assessment | OMR Entry, the system attempts to communicate with the OMR. If this handshake attempt is unsuccessful an error message will appear at the top of the screen.

Firstly, check that the OMR is connected and switched on. If so, check the OMR settings:

  1. Click the Setup button to display the OMR Setup form.

  2. Click the OMR Port Settings title tab.

  3. Make any adjustments necessary and click the OK button to return to the Read OMR screen (please see OMR Port Settings Page on page 412).

  4. Click the Retry button.

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