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1693 RLC Digibridge
3.11.7 Instrument Program
Commands
The set of commands used in remote programming
is an input data code to which the instrument will
respond as a "talker/listener", after being put into a
remote-control mode via the bus (see Table 3-25 on
page 95) and addressed to listen to device-dependent
command strings.
Refer to Table 3-19. The programming command set
includes all of the keyboard functions except switch-
ing external bias ON/OFF and Cull recalibration,
which are not remotely programmable. Keyboard
functions are explained above, particularly in para-
graphs 3.3, 3.4, 3.8, 3.9, 3.10; and most of these
commands are related to them in an obvious way.
Zero calibration by remote control is similar to the
manual procedure. The "Z1" command is equivalent
to manually keying [1] [6][9] [3][=] [SHIFT][OPEN].
It is necessary to allow the Digibridge to reach range
1. (It must not be held on another range.) The test
fixture must be physically open-circuited. Zero cali-
bration is initiated by a "G0" command (equivalent
to pressing START), which should not be followed
by other commands until the Digibridge responds
with ''SRQ". (The purpose of the "Z0" command is
to defeat the preceding "Z1" command, as you might
wish to do if the "Z1" was sent by mistake.)
Limit entry commands are interpreted in relation to
the previously established parameter; send the "M"
command first. Use the limit entry commands in the
tabulated sequence, except that nominal value need
not be repeated after once being entered.
Notice that f, n, h, and 1 in the table are "E-notation''
numbers, containing any number of digits, with op-
tional use of decimal point and optional use of power-
of-ten multiplier. Do NOT omit the semicolon after
each of these. (Refer to the table.) The letter n in the
table is nominal value in base units (ohms, farads, or
henries). For example, nominal value can be set to
543.21 pF by the command:
N543.21E-12;
74
Limits for bins 1 thru 13 are entered using percent-
ages, referred to the current nominal value. For
example, Bin No.1 (designated 01) is set to +1.5%,
-.05% by the command sequence:
B01H1.5;L-5E-2;
However, the limit for Bin Zero (the desired upper
limit for D or Rs or Q with R, lower limit for Rp or Q
with L) is entered as a value (dimensionless for D or
Q, ohms for R). For example , Bin Zero is set to 250
ppm (with parameter select ion C/D) by the command:
B00H250E-6;
Frequency is entered in kilohertz. H the desired
frequency is (for example) 3.25 kHz, the following
command will select the nearest available frequency,
which is 3.3333 kHz:
F3.25;
There are three types of commands: two-byte, three-
byte, and floating-point , as described below, Each
byte is coded according to the 7-bit ASCII code,
using the DI01...DI07 lines. The most significant
bit is DI07, as recommended by the Standard. (The
eighth bit – DI08 - is ignored .) Thus , for example ,
the command for "MEASURE FUNCTION' is P0,
having octal code 120 followed by 060. The two 7-bit
binary bytes are therefore: 1 010 000 and 0 110 000.
Note: The ASCII code - "X3.4-1968, Code for
"Information Interchange" - is available from
American National Standards Institute, 1430
Broadway, NewYork, N.Y. 10018. This code can be
written out as follows. For the numerals 0, 1, 2 ... 9,
write the series of octal numbers 060, 061, 062 _.. 071;
for the alphabet A, B, C ... Z, write the series 101, 102,
103 ... 132. (Refer also to the table in the paragraph
about "Address", in 2.8.4.) The ASCII code conforms
to the 7-bit code ISO 646 used internationally.
Two Byte and Three Byte Entries. These command
entries, as shown in Table 3-20, are simple ASCII
character sequences of two or three characters. The
first character is a letter which designates the category
of the entry. The following ASCII character - or two
characters if this is a three-byte entry - are decimal
Operation
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