Specifications

way to avoid the numbers, but that is limited to the 8-byte data format. For speed,
use FORM REAL,32 which is only four bytes per element.
Agilent VEE 4.0 does include in its Main Properties the ability to detect the infinity
numbers generated by IEEE-754 and to force 9.9E37 numbers, but it will be more
efficient to let the VT1419A keep from generating the IEEE-754 numbers.
Selecting the
FIFO Mode
The VT1419A’s FIFO can operate in two modes. One mode is for reading FIFO
values while algorithms are executing, the other mode is for reading FIFO values
after algorithms have been halted (ABORT sent).
·
BLOCking: BLOCking mode is the default and is used to read the FIFO
while algorithms are executing. Application programs must read FIFO
values often enough to keep it from overflowing (see “Continuously
Reading the FIFO” on page 83). The FIFO stops accepting values when it
becomes full (65,024 values). Values sent by algorithms after the FIFO is
full are discarded. The first value to exceed 65,024 sets the
STAT:QUES:COND? bit 10 (FIFO Overflowed) and an error message is
put in the Error Queue (read with SYS:ERR? command).
·
OVERwrite: When the FIFO fills, the oldest values in the FIFO are
overwritten by the newest values. Only the latest 65,024 values are
available. In OVERwrite mode, the module must be halted (ABORT sent)
before reading the FIFO (see “Reading the Latest FIFO Values” on
page 84). This mode is very useful when it is necessary to view an
algorithm’s response to a disturbance.
To set the FIFO mode (blocking is the *RST/Power-on condition):
[SENSe:]DATA:FIFO:MODE OVERWRITE select overwrite mode
[SENSe:]DATA:FIFO:MODE BLOCK select blocking mode
Programming the VT1419A Multifunction
Plus
Defining Data Storage
76 Chapter 3
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