Hand Held Products SV Series User Manual

Contents

8 - 4 Quick Check® SV Series User’s GuideNote: When in this sync mode, the sync input is a background application. TheSV Series will scan, analyze and report on bar codes as they passthrough the beam in this mode, regardless if a sync signal is sensed. Thepresence of a sync signal allows the number of codes expected(programmed) during the sync period to be used for a No Read condition.The absence of a sync signal results in operation similar to the Free ScanOperation described later.Sync Mode – Stationary Bar CodesIn this mode, a bar code(s) are placed in the beam and held in a known position.A sync input commands the SV Series to turn on the laser beam, perform aprogrammable number of scans, report the analyses and turn off the laser beam.A ~SA communication sync command is the most common sync source in thismode.Note: The SV Series must be programmed for Picket Fence travel orientation inthis mode if the bar codes are stationary when being scanned.No Sync – Free Scan OperationIn this mode, a sync signal is not used and the SV unit scans and analyzes barcodes at random as they pass through the laser beam. As stated in the SyncInput section, this mode is not recommended because it cannot report on missingor undetectable bar codes that can be caused by printer or other systemcomponent failures. This mode is most acceptable when the SV Series is usedas a bar code decoder only.It is recommended to use serial communications to a host in this mode for thehost to determine missing codes.If this mode is used, the SV Series can still detect many print errors because ofits partial decode analysis capability. This algorithm can detect a bar code startor stop character and two adjacent characters. This part of a code is usuallypresent in most print failure situations.For maximum reliability for partial decode analysis, the bar code(s) beinganalyzed must be present in the laser beam for 10 scans (example: 100milliseconds for SV units with 100 scans/analyses per second performance). Tocalculate bar code travel speed in this mode, see "Bar Code Travel SpeedConsiderations" on page 5-3. Calculate the maximum speed for the applicationper those instructions and then divide the speed by two for this application.Parameters AnalyzedFor each bar code scanned and analyzed, the SV Series performs practically allthe ISO, traditional and laser based verification methods documented in industryspecifications. All analysis parameters for these methods are reported via serialcommunications (see "Serial Port Transmission Format" on page 3-1) and mostof the parameters can be used in any combination to activate the five ports. Theanalysis parameters performed are listed below in the same order of thestandard transmission format as applicable.