Agilent Technologies 8510C, Operating And Programming Manual

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GPIB Programming Basics
DEFM7; to select Memory 7
DEFM8; to select Memory 8
First select the memory using the DEFM n ; instruction, turn on
memory b y issuing a DISPMEMO; instruction, then use OUTPMEMO; to
read curren tly selected memory . This transfers the memory data in
real/imaginary pairs.
Data Alw ays Comes from the Activ e Channel
Notice that there are t w o en tirely dieren t, parallel, data pro cessing paths sho wn in
Figure 13-1. One path is for Channel 1 and one is for Channel 2. Eac h c hannel has raw,
corrected, and formatted data arrays. Because the paths are separate and indep enden t,
dieren t features can b e active for Channel 1 and OFF for Channel 2. As y ou ha v e seen,
the GPIB transfer commands let y ou select the S-parameter (S11, S21, S12, or S22) for data
transfer. But since eac h c hannel has four indep enden t parameters, the data transfer alwa ys
o ccurs on the active c hannel.
Av ailable Data Transfer Formats
In remote programming, y ou can c ho ose one of four binary data formats, or an ASCII data
format.
Use the descriptions of eac h form to decide whic h transfer format is appropriate for y our
needs. Sp ecic information ab out b yte sizes and structure of these formats is pro vided in
\Preparing the Computer to T ransmit or Receiv e Data", later in this c hapter; and also in
the 8510C Network A nalyzer System Keywor d Dictionary .
F orm 1 (GPIB Command: FORM1 ) F ORM1 is signicantly dieren t from the other four
transfer mo des. The biggest dierence is that y ou can only obtain data from the
raw arra y when y ou use F ORM1. The other four transfer mo des let y ou c ho ose an y
in ternal data array for transfer.
F ORM1 is the fastest transfer format a v ailable and is almost exclusiv ely used
in fast CW mo de. Refer to \FORM 1" in the 8510C Network A nalyzer System
Keywor d Dictionary for a full description of this transfer format. F ORM1 data can
b e con v erted to oating p oint data in the computer. F ORM1 is the only transfer
format y ou can use for fast CW mo de.
F orm 2 (GPIB Command: FORM2 ) 32-bit IEEE 728 oating p oint format. This format is
not commonly used. It consists of a header, a t w o-b yte n um b er indicating ho w
man y b ytes follo w, then the real and imaginary data pairs for eac h stimulus p oint.
F orm 3 (GPIB Command: FORM3 ) This is the recommended format for use with HP 9000
Series 200/300 w orkstations. It consists of a header, a t w o-b yte n um b er indicating
ho w man y b ytes follow, then the real and imaginary data pairs for eac h stimulus
p oint. F ORM3 follo ws the 64-bit IEEE 728 standard format.
F orm 4 (GPIB Command: FORM4 ) This format is ASCI I and is not as commonly used as
other formats b ecause it is relativ ely slow. Ho w ev er, ev en with this limitation there
are still t w o circumstances in whic h F ORM4 is useful:
When rst learning ho w to transfer data. F ORM4 comes out in ASCI I format
that is meaningful to a h uman b eing.
13-8 GPIB Programming