National Instruments GPIB-SCSI-A, Руководство пользователя

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Chapter 5 S Mode Functions
© National Instruments Corp. 5-111 GPIB-SCSI-A User Manual
wrt (continued)
The
wrt
operation terminates when one of the following
events occurs:
• The GPIB-SCSI-A successfully transfers all data.
• The GPIB-SCSI-A detects an error.
• The I/O time limit is exceeded.
• Device Clear (DCL) or Selected Device Clear (SDC)
command is received from another device that is
Controller-In-Charge (CIC).
After
wrt
terminates, the GPIB-SCSI-A records the number
of data bytes it actually wrote to the GPIB. If one of the
events described above occurs (except if the GPIB-SCSI-A
successfully transfers all data), the count may be less than
expected.
If the GPIB-SCSI-A is CIC,
wrt
causes the GPIB-SCSI-A to
address itself to talk if it is not already addressed. The
GPIB-SCSI-A also addresses the device indicated by the
Address values in the CDB to listen.
The GPIB-SCSI-A then places itself in Standby Controller
state with ATN* off and remains there after the write
operation is complete.
The GPIB-SCSI-A must be CIC to perform the addressing.
If this is the first function you call that requires GPIB
controller capability and you have not disabled System
Controller capability with
rsc
, the GPIB-SCSI-A sends
Interface Clear (IFC*) to make itself CIC. It also asserts
Remote Enable.
The only possible errors are EABO (if the I/O time limit is
exceeded), ECIC (if you passed control to some other GPIB
device and control has not been returned to you or you have
not sent IFC to make yourself CIC before making this call),