Table of Contents
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SECTION 4
GPIB
Interface
4.5.1
Setting Messages
An instruction
used to perform an instrument
setting or
operation
is called a setting message. The setting mes-
sages for the instrument
are provided by Table 4-8.
Examples of setting messages:
"FR lOE3" -
Sets frequent
to 1OkHz.
"DA 0" -
a
DISPLAY,
B
b
DISPLAY
and CRT are
placed in the automatic selection mode.
CAUTION
Note that the zero correction
operation
of
OPEN and SHORT and the measurement
in
the manual trigger mode are held up when
the next program
code is received
during
their execution.
4.5.2
Inquiry Messages
An instruction to read an instrument setting or the meas-
ured data is called an inquiry message.
Each message
consists of the inquiry header that is preceded with 'I?".
Inquiry messages are listed in Table 4-9. The response to
the message is in the format of "header" + "parameter" +
"delimiter".
Headers
The output of a header is optional. The header output is
inhibited when power is turned on or when the device
clear command is received.
Parameters
The following formats are available for parameters.
The
type of output and the number of digits (number of let-
ters) are determined
according to the inquiry messages.
l
NRl: Integer
"0", "l", etc.
l
NR2: Floating-point
representation
(no exponent part)
"12.345", etc. When this format is used, the position of
the decimal point may be fixed or variable.
l
NR3: Exponent representation
(with exponent part)
"15.75E+03",
etc.
When this format is used, the exponent
becomes
a
multiple of 3 in the range of E-12 (lo-'? to E+06 (106)
+
which is consistent with the how the front panel dis-
play handles exponents.
Generally, a zero in NR3 is expressed by making both
the mantissa
and exponent
zeros
("0.0000E+00").
However, for a measured value, only the mantissa be-
comes zero.
Notes:
1. Leading zeros are omitted (except for one zero be-
fore a decimal point), and data is right-justified.
2. The plus sign (+> for positive numbers is omitted.
However,
the plus sign (+) for the exponent
is in-
cluded. The exponent always has two digits.
Delimiters
The following
two delimiters
can be selected from the
front panel:
l
<CR> <LF> (carriage return and line feed)
l
<CR> (carriage return only)
The END message is output with the last letter (the last
letter after a delimiter) of the response of the instrument
to an inquiry (EOI line = Low).
Notes
When the instrument
is programmed
as a talker
without sending an inquiry message, a single blank
and a delimiter are output except immediately
after
a measurement
is performed
in the manual trigger
mode.
When more than one inquiry is performed,
only the
last inquiry is valid. Other inquiries are ignored.
The response to an inquiry is canceled when the fol-
lowing operation is performed without receiving the
response after sending an inquiry command.
l
Program code "TG"
l
GET command
Example of response to inquiry:
"?FR" (Frequency)
- "lE+03"
or "FR lE+03"
"?DT" (Measured value) - "123.45E-03,0.0012"
or
"DT 123.45E-O3,0.0012"
The example responses are shown with and without
the header.
4-13
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