Opticon NFT 2135, NFT 1125 manual Application Notes, Tips for Achieving High Throughput

Manual No. 25-NFT1121-01

Series NFT-1121/2135 Mini CCD Fixed Position Scanners

Application Notes:

Tips for Achieving High Throughput

In some applications your primary objective may be to achieve the highest possible throughput rate. The following list identifies the parameters and scanner settings that can maximize scanning and decode throughput speed. Note, by emphasizing maximum throughput, other areas of performance may be affected. For example, the number of non-reads could increase.

If high throughput is critical, consider some or all of these settings:

♦Operate in the Trigger Disabled mode. Operation of the trigger can require as much as 200 msec before decoding begins, slowing down throughput rate.

♦Only enable those symbologies that you will be decoding.

♦Eliminate all suffixes and prefixes.

♦Minimize the number of redundant reads required before transmitting data.

♦Transmit the decoded data at the highest baud rate, 19200 baud.

♦Disable both the hardware and software buzzer functions.

♦If you need a buzzer, use the hardware buzzer rather than the software buzzer.

Tips for Insuring Highest Data Integrity

There are several parameters that can enhance your confidence that the correct bar code data is transmitted. Note that by emphasizing the accuracy and security of the data other areas of the scanner operation may be affected, for example, you may not achieve the highest throughput.

If accuracy and data integrity are critical, consider some or all of these settings:

♦Program the scanner to require a high number of redundant decodes prior to transmitting. For example, program the scanner to decode a bar code exactly the same way three consecutive times before transmitting the data. Then decoding the bar code the same way 2 out of 3 times or any 3 out of 4 times is not sufficient. It must obtain three consecutive and identical decodes.

♦Utilize a predetermined, fixed-length of bar code. Program the scanner to only decode a bar code of that length. Bar codes of any other length will be ignored.

♦The quality of the printed bar code must be excellent.

♦Use a bar code symbology that contains an internal check digit and program the scanner to calculate that check digit for validity prior to transmitting.

♦Do not use a symbology with poor internal verification, or subject to partial decodes, such as 2 of 5 or MSI/Plessey.

♦Only enable those symbologies that you will be decoding.

♦Transmit data at low baud rates to minimize communication errors.

♦Enable the “Number of Characters Transmitted.” The scanner will calculate and transmit a number indicating the total number of characters it is transmitting. Your host application program can compare this number with the actual number of characters received to verify that the correct amount of data is received.

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