Sdc (Selective Device Clear); Get (Group Execute Trigger) - Keithley 199 Instruction Manual

lEEE-488
PROGRAMMING
To send the DCL command, the controller must perform
the following steps:
1. Set ATN true.
2. Place the DCL command byte on the data bus.
Notes:
1. DCL will return the instrument to the default line fre-
quency setting.
2. DCL will not have any effect on the current IEEE
address.
Programming Example--Place the unit in an operating
mode that is not a default condition. Now enter the follow-
ing statement into the keyboard:
Note that the instrument returns to the default conditions.
3.8.6 SDC (Selective Device Clear)
The SDC command is an addressed command that per-
forms essentially the same function as the DCL command.
However, since each device must be individually address-
ed, the SDC command provides a method to clear only
a single, selected instrument instead of clearing all in-
struments simultaneously, as is
the
case with DCL.-When
the
Model
199 receives the SDC command, it wil1 return
to the default conditions (see paragraph 3.9.11). Table 37
lists factory default conditions.
To transmit the SDC command, the controller must per-
form the following steps:
1. Set ATN true.
2. Address the Model 199 to listen.
3. Place the SDC command byte on the data bus.
Notes:
1. SDC~ will return the instrument to the default line fre-
quency setting.
i. <DC
will not have any effect on the current IEEE
address.
Programming Example-Using several front panel con-
trols, alter instrument states from the default configura-
tion Send SDC with the following statement:
When the above statement is executed, the instrument
returns to the default configuration.
3.8.7 GET (Group Execute Trigger)
GET
may
be used to initiate a Model 199 measurement se-
quence if the instrument is placed in the appropriate trig-
ger mode (see paragraph 3.9). Once triggered, the instru-
ment will take a single reading or series of readings.
To send GET the controller must perform the following
sequence:-
1. Set ATN low.
2. Address the Model 199 to listen.
3. Place the GET command byte on the data bus.
Programming Example-Type in the following statements
to place the instrument in the correct hitzger mode for pur-
poses of this demonstration:
Now trigger the reading by sending GET with the follow-
ing statement:
The reading will be triggered when the statement is
executed.
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