Boonton 1121A, Instruction Manual

Page: 43 / 181

Operation Section 3
3-21
3-84. Returning to Local Mode. The instrument may be
returned to the local mode as follows:
a. The LCL/INIT key is depressed, provided local
lockout (LLO) is not active.
The instrument must be placed in the remote
mode for it to store and respond to data mes
sages.
3-85. Triggered Operation.
In the remote mode the
instrument can be operated in the immediate mode
(mnemonic IM), or in the wait-for-trigger mode (WT). The
immediate mode is the default condition and results in the
immediate response to mnemonic commands and
settings. The wait-for-trigger mode causes the execution
of commands and settings to be deferred until a trigger is
received. This aids in synchronizing the instrument’s state
changes to other system components. The wait-for-
trigger mode is set when the WT mnemonic is encoun-
tered in the input string. From that point on execution is
delayed. No change will occur until one of the following
events is encountered:
a.
“Group-execute-trigger” (GET) is received.
b. The mnemonic TR (trigger) is interpreted.
c. Any mnemonic following IM (immediate) is
interpreted.
NOTE
Event (c), above, or go-to-local terminates the
wait-for-trigger mode and restores the immediate
mode. The wait-for-trigger mode is not active in
location operation.
3-86. Talk Operation.
The instrument may be addressed
as a talker without regard for remote/local mode. When
the talker state is set by the bus controller, the instrument
sends a character string which is determined by the
current talk mode. One of six different talk modes is
selected by sending the appropriate mnemonic with the
Model 1121A addressed as a listener. The selected mode
will remain in effect until changed.
3-87. Talk Status (TS) Mode. In the TS mode the error
code status of the instrument is returned as a number.
Normal status returns a 0 code otherwise the error num-
ber is returned. The TS mode will automatically clear the
error after the status is reported. The TS mode is the
default talk mode after initialization of the instrument.
3-88. Talk Value (TV) Mode.
In the TV mode the ar-
gument of the active function designated by the KYBD
annunciator is returned as a number. All values returned
are in basic units such as: Hz, V, dB, etc.
3-89. Talk Program (TP) Mode.
In the TP mode a 10
digit number is returned that uniquely identifies the firm-
ware and installed optional filters. A radix separates the
firmware date code and the optional filter identification
number. The 4 digit code to the right of the radix will
correspond to the codes listed in Table 5-2.
3-90. Talk Function (TF) Mode.
In the TF mode a
variable length string of ASCII characters will be returned
which identifies the state of all active functions. The bit
assignments are arranged to allow for string or byte
oriented decoding. The various characters are listed in
Table 3-11.
3-91. Talk Learn (TL) Mode.
In the TL mode a com-
pressed parameter string of 169 ASCII characters, the
last of which is an ASCII ($), is returned. This string can
be sent back to the instrument at any time to restore the
exact state of all functions and settings which defined it,
but it must be sent as a complete string without alteration.
When the ($) character is encountered in the input buffer,
the learn mode is automatically activated. While this form
provides a compact and fast method to save and restore
all settings, it bypasses much of the error control and
must be used with caution.
3-92. Talk Burst (TB) Mode.
In the TB mode a com-
pressed parameter string of 21 ASCII characters, the last
of which is an ASCII (&), is returned. Like the Learn
string, this string can be sent back to the instrument at
any time to restore the exact state of the source level and
frequency settings which defined it, but it must be sent as
a complete string without alteration. While this form
provides a compact and fast method to save and restore
frequency and amplitude setting to create sweep or tone
burst sequences, it bypasses update of the display and
much of the error control and must be used with caution.
To prevent the display from giving false indications the
display may be blanked using the (BL) command.
b. The go-to-local (GTL) bus command is sent.
c. Remote enable (REN) is set false.
NOTE