Microscan MS-9 User Manual page 207

Appendices
Improving the Number of Decodes
After changing any of the parameters described here, recalculate number of decodes.
Scan Speed
Scan speed is a function of motor speed and is adjustable. A slower scan rate may allow
greater symbol range and/or higher decode rates, but at the cost of a lower decode rate
scans. When you lower scan speed, you lower the decode rate.
Range
Adjusting the symbol's range, if possible, is one of the quickest and most effective ways
to improve decode rates. However, in some applications you may need to select a less
than optimum range, or one that is beyond the fringes of the ranges.
Scan Width
Increasing scan width will increase the number of scans in a picket fence oriented appli-
cation. Scan width is linked with scan range and changing one will usually require a
change in the other.
Symbol Speed
Applies to both picket fence and ladder oriented symbols. If your application allows it,
slowing symbol speed (the time in seconds that a symbol is fully within the scan width
of the scanner) is an effective way to increase the number of decodes.
Laser Framing
Narrowing the laser frame may not increase the decode rate, but it will minimize the
opportunity of extraneous reads.
Symbol Dimensions, Symbol Density, and Symbol Ratio
Not usually an option in most applications, but changes to symbol parameters can
affect number of decodes calculations and possibly decode rates.
If your application allows, shortening the length of a picket fence symbol means the sym-
bol will be in the read range longer and hence receive a greater number of scans.
Increasing the height of a ladder symbol means it will receive more scans. Changing
symbol density and/or symbol ratio is another way ranges, decode rates can be altered.
Gain
This adjustment, typically made by qualified technicians, is referenced in the Scanner
Setup menu under Read Cycle. (See
"Scanner Setup" on page 4-17.)
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MS-9 Scanner User's Manual