User`s guide

77
Chapter 3 System Overview
Measurement Input
3
Main Processor The main processor, located in the floating logic
section, controls the input signal conditioning, ranging, and the ADC.
The main processor accepts commands from, and sends measurement
results to, the earth-referenced logic section. The main processor
synchronizes measurements during scanning and control operations.
The main processor uses a multi-tasking operating system to manage the
various system resources and demands.
The main processor also calibrates measurement results, performs
Mx+B scaling, monitors alarm conditions, converts transducer
measurements to engineering units, time stamps scanned
measurements, and stores data in non-volatile memory.
Scanning
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.
Before you can initiate a scan, you must set up a scan list 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.
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. Each time you start a new scan, the
instrument clears all readings stored in memory from the previous scan.
Therefore, all readings currently stored in memory are from the most
recent scan.
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