3. HAL Properties
Advent Instruments Inc.
FSK
Controls the FSK demodulator, which decodes a FSK signal into a stream
of byte values.
SOURCE
Determines the signal source for measurement meters, DTMF detector,
FSK decoder, and BNC output connector.
Waveform Capture & Playback & Transfer:
ACCAP
Controls the capture and playback of AC signals.
DCCAP
Controls the capture of DC line voltage and loop current measurements.
BULK
Collection of properties that simplify the transfer of AC or DC waveform
data to and from the PC.
System Related Functions:
SYSTEM
Collection of properties controlling system related functions.
COMM
Controls the RS-232 serial port settings.
USB
Controls the USB port settings.
DIO
Determines the function of the rear panel digital Input/Output connector.
FILE
Collection of properties used to access files stored in the flash memory.
TIMER
Collection of properties that represent various timers used in the system.
SIGNALIO
Sets the gain of any signals routed to the BNC output connector.
STATUS
Properties returning status information on various AI-7280 activities.
SCHEDULER
Method to perform various operations at a predetermined future time.
Each property is of either a numeric or string data type. If a numeric property then its
value can represent any single precision floating point value. Otherwise as a string
property, its value is represented by a string of characters. For the string data types, the
maximum length supported is 64 characters. The null character (0h) is used internally to
mark the end of a string. As such, null (0h) cannot be used within a character string.
All of the properties in the following sections are listed in alphabetical order. For a listed
by ID number, see: Appendix B: Property Listing by Index
Note: The property descriptions that follow assume an AI-7280 firmware version of at
least 4.14. If an earlier version is used, some of the following properties may not be
available. It is recommended that the AI-7280 be upgraded to the latest firmware
version. A software package to update the firmware is available on the
www.adventinsturments.com web site.
3.2 ACCAP Properties
These properties are used to capture AC signals and optionally play them back. Up to
229376 samples can be collected at either the full sample rate (39062.5 samples/s) or at
the half sample rate (19531.25 samples/s) depending on the MODE property value. In
either case, the samples are stored as 16 bits values representing a maximum range of +/-
10V. The samples are stored in an internal memory buffer with the INDEX property
pointing to where in the buffer the next sample is to be stored. The signal source for the
capture is determined by the SOURCE.ANALYZER property.
Samples stored in the buffer may be played back by using the PLAYINDEX and
PLAYCOUNT properties. The MODE property affects the playback sample rate as well
as the capture rate. If half rate playback is selected, then cubic interpolation is performed
in order to up sample to the full system sample rate. The playback samples are summed
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AI-7280 Programmers Guide - Direct Control