HandHeld Entertainment SV Series How to Set Up Single Scan Operation, Checking SV Status with ~HT

The major trade-off to the single scan feature is only one bar code at a time can

be analyzed in the beam vs. up to 4 codes in picket fence mode in the standard

system. The major disadvantage to this method in cases where only a single

scan is used for evaluation of a bar code is there is a higher probability that the

analyses may not be accurate because part of the scan could be at the upper or

lower edges of one or more of the elements in the code. Therefore if most of the

analyses are being calculated with a single scan, this type of operation is

recommended for measuring print trends in high volume, high speed applications

where some small percentage of analyses that randomly indicate an unusual low

grade can be filtered out.

In the case the bar code is in the laser beam for more than a single scan, all the

scans gathered are averaged in the symbol analysis just like standard SV

operation.

The special single scan operation is enabled only in Ladder Orientation mode.

Picket fence Orientation mode operation is not affected. The travel direction of

the codes can be either picket fence or ladder. The reason for using ladder mode

is it limits the number of codes that can be simultaneously analyzed in the beam

to a single code.

How to Set Up Single Scan Operation

Three commands that set up the operation are ~SB1 and ~LS01 and ~Hnx (x can

be 2, 3, 4, or 5). The SV must also be placed in "Ladder" mode and the code must

be in the ladder zone to be scanned and analyzed.

~SB 1 (~SB0 is the normal setting) enables the system to let the initial scan of a

code pass to the analysis algorithms rather than wait for one of the next two

scans to be a duplicate before the code is allowed to be analyzed.

~LS01 allows the initial scan to be reported as a 1 scan average in case the code

leaves the beam before a second scan is detected.

~Hnx is a command that programs the number of consecutive scans that do not

detect a bar code that cause the code to exit the beam and be reported. The

standard system operation is fixed at 5. ~Hnx can be programmed for 2, 3, 4, or

5 scans. A lower number will allow a higher duty cycle, but it may also be less

stable if a code is static in the laser beam, therefore causing multiple reports.

Checking SV Status with ~HT

The normal way of checking system status is with the ~HT command. The newer

commands ~SB and ~Hn are not displayed with the standard ~HT command. In

order to display the additional commands, set command ~De1 to allow the

alternate ~HT reply.