Timers

The Timers Parameter Programming Mode controls the two NCR 7879 timers: Lockout Time and Active Time. The default values are shown in the Red boxes and also in the Parameter Defaults section earlier in this chapter.

Lockout Time

The lockout timer prevents the scanner from repeatedly reading the same bar code. After reading a bar code, it must be removed from the Scan Zone and the time programmed in the lockout timer must elapse before the scanner can read the same bar code again. The Lockout Time parameter selects the lockout time.

There are 9 specific times ranging from 350 milliseconds to 1500 milliseconds. Select these times using the Hex 0 through Hex 8 tags.

Restart Lockout Timer

The Restart Lockout Timer parameter controls restarting the lockout timer each time the scanner reads the same bar code. Turning on the Restart Lockout Timer option has the following effect. If a bar code moves out of the scan pattern after being read and then back into the scan pattern before the lockout timer times out, the lockout timer restarts. The Hex 0 tag turns off this option and the Hex 1 tag turns it on.

Active Time

The specific lengths of time that the NCR 7879 stays ON after the last good read can be programmed. There are four options in the Active Time parameter: no shut down, shut down after 15 minutes, shut down after 30 minutes, and shut after 60 minutes. Select these times using the Hex 0 through Hex 3 tags, respectively.

Note:  NCR suggests that the Active Time parameter not be set to 0. When set to 0, the imaging system is ON all the time.

900 ms Lockout Timer Restart Limit

The 900 ms Lockout Timer Restart Limit parameter is disabled by default. Scan Hex 1 to enable the 900 ms Lockout Timer Restart Limit. If enabled, the lockout timer cannot be restarted if 900 ms have elapsed after the bar code leaves the Scan Zone. If an item moves into the Scan Zone and the tag is read and then moves out and back into the Scan Zone, the firmware recognizes the bar code is the same bar code that was just read. In this case, the Lockout Timer can be restarted only if it has been on for less than 900 ms.

Note:  The 900 ms Lockout Timer Restart Limit parameter has no effect unless the Restart Lockout Timer is on and the Lockout Time parameter is set for greater than 900 ms: Options 4, 5, 6, and 7.