Chapter 5 Remote Interface Reference

Scanning Overview

Scanning Overview

See also “Scanning” in chapter 4 starting on page 74.

The instrument allows you to combine a DMM (either internal or external) with multiplexer channels to create a scan. During a scan, the instrument connects the DMM to the configured multiplexer channels one at a time and makes a measurement on each channel.

Any channel that can be “read” by the instrument can also be included in a scan. This includes any combination of temperature, voltage, resistance, current, frequency, or period measurements on multiplexer channels. A scan can also include a read of a digital port or a read of the totalizer count on the multifunction module.

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∙ Before you can initiate a scan, you must set up a v to include all desired multiplexer or digital channels. Channels which are not in the scan list are skipped during the scan. The instrument automatically scans the list of channels in ascending order from slot 100 through slot 300. Measurements are taken only during a scan and only on those channels which are included in the scan list. The “ ” (sample) annunciator turns on during each measurement.

You can store up to 50,000 readings in non-volatile memory during a scan. Readings are stored only during a scan and all readings are automatically time stamped. If memory overflows (the MEM annunciator will turn on), a status register bit is set and new readings will overwrite the first readings stored (the most recent readings are always preserved). You can read the contents of memory at any time,

even during a scan. Reading memory

cleared when you read it.

Each time you start a new scan, the instrument clears all readings (including alarm data) stored in reading memory from the previous scan. Therefore, the contents of memory are always from the most recent scan.

If you abort a scan that is running, the instrument will complete the one measurement in progress (the entire scan will not be completed) and the scan will stop. You cannot resume the scan from where it left off. If you initiate a new scan, all readings are cleared from memory.

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HP 34970A manual Scanning Overview, See also Scanning in starting on