Keithley 6512, Instruction Manual

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IEEE-488 Programming
3-23
tails. Whatever primary address you choose, you must make
certain that it corresponds with the value specified as part of
the controller’s programming language.
To check the present primary address, or to change to a new
one, use the following sequence:
1. Press the PROGRAM SELECT button, and note that the
following message is displayed:
IEEE 27
2. This message indicates that the IEEE address program is
selected, along with the presently programmed value (in
this case, the default value of 27 is being displayed).
3. Using one of the ADJUST buttons, scroll the displayed
address to the desired value from 0 to 30 (the display
will show special values for the talk-only mode, as de-
scribed in the next paragraph).
4. Exit the program by pressing SHIFT then SELECT EX-
IT. The new address is now in effect, and it will remain
programmed even if the power is turned off.
NOTE
Each device on the bus must have a unique
primary address. Failure to observe this
precaution will result in improper bus op-
eration.
3.5 Talk-only mode
The Model 6512 may be placed into the talk-only mode and
be used with a listen-only device such as a printer. When in
this mode, the instrument will ignore commands given over
the bus and merely output data as requested by the listening
device. When the instrument is in the talk-only mode, the
front panel TALK LED will turn on.
The instrument can be placed in the talk-only mode by enter-
ing one of the following parameters in the primary address
program:
40 Talk-only mode with prefix on data string
(Example: NDCV-1.2345E-01)
41 Talk-only mode without prefix on data string
(Example: -1.2345E-01)
To place the instrument in the talk-only mode, perform the
following steps:
1. Press the PROGRAM SELECT button so that the fol-
lowing message is displayed:
IEEE 27
2. Press the up arrow ADJUST button repeatedly until the
desired talk-only parameter (40 or 41) is shown.
3. To exit the program, press SHIFT then SELECT EXIT.
The unit is now programmed for the talk-only mode, and
it will remain programmed in this manner even if the
power is turned off.
Selecting the data output rate
The data output rate in the talk-only mode can be selected as
follows:
1. Press and hold the DATA STORE ON/OFF button until
the desired rate is displayed, as indicated below.
Displayed r Value/data output rate
_______________________________________
r=0 Conversion Rate (Every 360msec)
r=1 One reading per second
r=2 One reading every 10 seconds
r=3 One reading per minute
r=4 One reading every 10 minutes
r=5 One reading per hour
r=6 One reading each time TRIG is pressed
2. Press the PROGRAM SELECT button until the IEEE
program message is displayed, and then release the but-
ton. Select the desired IEEE-488 talk-only parameter
(40 or 41) using an ADJUST button.
3. Press SELECT EXIT to return to normal operation. The
instrument will then enter the talk-only mode and output
readings over the IEEE-488 bus at the selected interval.
3.6 Front panel messages
The Model 6512 has a number of front panel messages asso-
ciated with IEEE-488 programming. These messages are in-
tended to inform you of certain conditions that occur when
sending device-dependent commands to the instrument.
The following paragraphs describe the front panel error mes-
sages associated with IEEE-488 programming.