Idiomas disponibles
Idiomas disponibles
3 Features and Functions
Scanning with External Instruments
In this configuration, you can use the DAQ970A/DAQ973A for signal routing or control applications. If you install a
multiplexer plug-in module, you can use the DAQ970A/DAQ973A for scanning with an external instrument. You can
connect an external instrument (such as a DMM) to the multiplexer COM terminal.
To control scanning with an external instrument, two control lines are provided. When the DAQ970A/DAQ973A and
the external instrument are properly configured, you can synchronize a scan sequence between the two.
In this configuration, you must set up a scan list to include all desired multiplexer or multifunction 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.
For an externally-controlled scan, you must disable the internal DMM by pressing [Home] > User Settings > DMM
Off. Since the internal DMM is disabled, readings from multiplexer channels are not stored in internal reading
memory.
External connections are required to synchronize the scan sequence between the DAQ970A/DAQ973A and the
external instrument. The DAQ970A/DAQ973A must notify the external instrument when a relay is closed and settled
(including channel delay). The DAQ970A/DAQ973A outputs a Channel Closed pulse from pin 5 on the rear-panel
connector. In response, the external instrument must notify the DAQ970A/DAQ973A when it has finished its
measurement and ready to advance to the next channel in the scan list. The DAQ970A/DAQ973A accepts a Channel
Advance signal on the External Trigger input line (pin 6).
You can configure the event or action that controls the onset of each sweep through the scan list (a sweep is one
pass through the scan list). When the DMM is disabled, the default scan interval source is "Auto" (Immediate). For
more information, refer to Scan Interval. You can configure the event or action that notifies the DAQ970A/ DAQ973A
to advance to the next channel in the scan list. Note that the Channel Advance source shares the same sources as
the scan interval. However, an error is generated if you attempt to set the channel advance source to the same
source used for the scan interval.
You can specify the number of times the instrument will sweep through the scan list. When the specified number of
sweeps have occurred, the scan stops.
An externally-controlled scan can also include a read of a digital port or a read of the totalizer count on the
multifunction module. When the channel advance reaches the first digit channel, the instrument scans through all
the digital channels in that slot and stores the readings in reading memory (only one channel advance signal is
required).
You can configure the list of channels for 4-wire external scanning. When enabled, the instrument automatically
pairs channel n with channel n+10
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Keysight DAQ970A/DAQ973A User's Guide
