National Instruments GPIB-SCSI-A, Руководство пользователя

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S Mode Functions Chapter 5
GPIB-SCSI-A User Manual 5-6 © National Instruments Corp.
brd (continued)
Depending on the setting of Switch 5, you may have received
some bytes that do not represent true GPIB data. Therefore,
you should request and analyze the GPIB-SCSI-A status that
contains a count equal to the exact number of bytes read from
the GPIB. This number represents the number of valid data
bytes received.
The
brd
operation terminates when:
• The GPIB-SCSI-A successfully reads all data
• The GPIB-SCSI-A detects an error
• The I/O time limit is exceeded
• The END message is detected
• The EOS character is detected (if this option is enabled)
• Device Clear (DCL) or Selected Device Clear (SDC)
command is received from another device that is
Controller-In-Charge (CIC).
After
brd
terminates, the GPIB-SCSI-A records the number
of data bytes it actually read from the GPIB. If one of the
previous events occurs (except for the GPIB-SCSI-A
successfully reading all data), the count may be less than
expected.
The only possible errors are an EABO (if the I/O time limit is
exceeded) or an EADR (if the GPIB-SCSI-A has not been
addressed by the Controller to listen). If an error occurs, the
GPIB-SCSI-A will abort the command, issue a Check
Condition status response, and set the Sense Key to ERROR.
This command is referred to as Board-Level because it
performs none of the necessary GPIB addressing. All
addressing must be done by the CIC of the GPIB, or by the