User`s guide

99
Chapter 4 Features and Functions
Scanning
4
External Scanning In this configuration, the instrument sweeps
through the scan list once each time a low-going TTL pulse is received
on the rear-panel Ext Trig Input line (pin 6).
• You can specify a scan count which sets the number of external pulses
the instrument will accept before terminating the scan. See “Scan
Count” on page 102 for more information.
• If the instrument receives an external trigger before it is ready to
accept one, it will buffer one trigger before generating an error.
• All readings from the scan are stored in non-volatile memory.
Readings accumulate in memory until the scan is terminated (until
the scan count is reached or until you abort the scan).
• Mx+B scaling and alarm limits are applied to measurements during
the scan and all data is stored in non-volatile memory.
• Front-Panel Operation:
EXTERNAL SCAN
To initiate the scan, press . The EXT annunciator turns on as a
reminder that an External Scan is in progress. When a TTL pulse is
received, the scan starts and readings are stored in memory. To stop
scan, press and hold
.
Ext Trig Input
Gnd
Input
Ext Trig Connector
> 1 s
5V
0V
34970A Refresh UG.book Page 99 Wednesday, February 17, 2010 12:34 PM