Universal Menu Book/Code options/Setting of number of characters

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If you are going to read bar codes of known length, it is recommended to set the reader for a fixed number of characters. This can be done for up to two lengths. The reader uses this to verify that labels read are of the correct length, rejecting any labels which do not have the specified length. The advantage of setting a fixed length, is that it provides protection against short scans of labels, such as Interleaved 2of5, which do not provide sufficient security against partial scan. The length checking is done on the label data and is not affected by options such as (not) transmit start/stop character or check digit. Setting the number of characters does not affect fixed length codes, such as EAN-13. 2D symbologies such as PDF417 and Data Matrix are also not affected by fixed length settings.

The following options are available:

Fixed length OFF all codes.
This option cancels the fixed length checking.

Fixed length ON all codes.
This option enables the fixed length checking. Two fixed lengths are programmed which will affect all variable length codes. This is done by reading the following labels:
<SET>
<Fixed length ON - all codes> a bar code with the required length, a second bar code with the required length (this may be the same one as the first one)
<END>
See figure 3.06.

File:SettingFixedLengthONallcodes.svg

It is possible to configure a fixed length or a minimum and a maximum length for selected symbologies by reading the respective option followed by a barcode label with the required length. The different functions may be combined and will be used as follows:

  • If a label is checked for fixed length, it will not be checked for minimum or maximum length.
  • If a label is not checked for fixed length it will be checked for both minimum and maximum length.

By reading an option followed by the "END" label, the function is disabled or the values for that option are reset to their default. The default values are:

  • fixed: disabled, thus no fixed length checking
  • minimum: according to the next figure (The minimum length of the 2of5 bar code types can not be changed independent.)
  • maximum: disabled, thus no maximum length checking. (The maximum length is reader dependent)

See figure 3.07.

File:SettingMinimumLengthTable.svg

Fixed length ON for selected codes:
This option enables fixed length checking for different bar code types and will only affects the bar code types read. The number of fixed lengths which can be configured is reader dependent.
<SET>
<Fixed length ON for selected codes>
Scan bar codes of the required type and length
<END>

Example:
The 2 examples shown in the next figure have the following results: In the first example only Code 39 labels will be checked for a length of 6 characters. Any other bar code type will not be checked for fixed length. In the second example Code 39 labels will be checked for a length of 6 characters and Interleaved 2of5 labels for a length of 12 characters. This implies that also Industrial 2of5, Matrix 2of5 and S-Code are checked for a fixed length of 12 characters. Any other bar code type will not be checked for fixed length. See figure 3.08.

File:SettingFixedLengthONselectedcodes.svg

Minimum length for selected codes:
This option modifies the default minimum length table. The number of minimum lengths which can be configured is reader dependent. This is done by reading the following labels:
<SET>
<Minimum length for selected codes>
Scan bar codes of the required type and length
<END>

Example:
The two examples shown in the next figure have the following result: In the first example only Code 39 labels will be checked for a minimum length of 2 characters. All other bar code types will be checked for the minimum length as displayed in the next figure.

In the second example Code 39 labels will be checked for a minimum length of 2 characters and Interleaved 2of5 labels for a minimum length of 4 characters. This implies that also Industrial 2of5, Matrix 2of5 and S-Code are checked for a minimum length of 4 characters. All other bar code types will be checked for a minimum length as per figure 3.09.

File:SettingMinimumLenghtSelectedCodes.svg

Maximum length for selected codes:
This option enables the maximum length checking. The number of maximum lengths which can be configured is reader dependent. This is done by reading the following labels:
<SET>
<Maximum length for selected codes>
Scan bar codes of the required type and length
<END>

Example:
The two following examples shown in the next figure have the following result: In the first example only Code 39 labels will be checked for a maximum length of 12 characters. Any other bar code types will not be checked for a maximum length. In the second example Code 39 labels will be checked for a maximum length of 12 characters and Interleaved 2of5 labels for a maximum length of 14 characters. This implies that also Industrial 2of5, Matrix 2of5 and S-Code are checked for a maximum length of 14 characters. Any other bar code types will not be checked for a maximum length. See figure 3.10.

File:SettingMaximumLengthSelectedCodes.svg

Serial programming:
To set a length using serial command, the sequence is as follows:
<ESC>
<command>
<Space>*<Code ID>*
<Length 1>
<Length 2>
<CR>

  • (if required by command)

Example:
Setting fixed length for all codes, lengths 8, 10 and 12:

  • <ESC>H1081012<CR>

Setting minimum length for selected codes, for Code 39 with a length of 2:

  • <ESC> HL V02<CR>

Setting maximum length for selected codes, for Code 39 with a length of 12 and Interleaved 2of5 with length of 14:

  • <ESC>HM V12 N14<CR>
SET Image:MenulabelZZ.png
Fixed length OFF all codes H0 File:Menulabel H0.png
Fixed length ON all codes H1 File:Menulabel H1.png
Fixed length ON for selected codes HK File:Menulabel HK.png
Minumum length for selected codes HL File:Menulabel HL.png
Maximum length for selected codes HM File:Menulabel HM.png
END Image:MenulabelZZ.png
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