Keithley 194 Instruction Manual page 133

IEEE-488 PROGRAMMING
In this example program, the computer first places the in-
strument in remote (line 20), and then programs the in-
strument to generate an SRQ on error. The statement at
line 40 then attempts to program an illegal command (ElX).
The program then waits for an SRQ to occur on the bus
(lines 50 and 60), and then serial polls the instrument (line
70) and displays the status byte bits (lines 80-110). The er-
ror (Ul) status word is then requested and displayed in
order to clear the error bit in the status byte (lines 130-140).
Model 6573 Programming Example-Add the lines below
to the modified declaration file (paragraph 4.6.3) to
demonstrate SRQ and status byte programming.
COMMENTS
Send remote enable.
Build SRQ command
string.
Program for SRQ on
error.
Build illegal corn.
mand string.
Attempt to program
illegal option.
Wait for SRQ.
Serial poll the 194.
buffer. -
In the above program, the instrutlwnt is placed in "mote
(line 10) and the" programmed to generate an SRQ under
error conditions (lines 20 and 30). Next, an attempt is made
to program an illegal command (lines 40 and SO), and the
program then waits for the instrument to generate a" SRQ
(line 60). After the SRQ is generated, the instru"w"t is
serial polled (line 70). and the status bytes are the"
displayed (lines 90-130). Finally, the UI error condition
word is requested and displayed i" order to clear thr w
ror bit in the status byte (lines 140~180).
4.9.17 Channel (C)
The C command allows selcctio" of the chlmnel 1 111 cham
nel 2 A/D modules (for those instruments equipped 1o1
dual-channel operation). Options of this command arc
summarized in Table 4-24.
Table 4-24. Channel Control Commands
Select Channel 2
*NOTE: Selected channel determines which channel is af-
fected by other device-dependent commands.
Upon power up, or after a DCL or SDC command, chdw
nel 1 will be selected.
C command options include:
A/D channel control (Cl and C2): Sending one of these
commands will select the corresponding A/D module. The
selected module determines the source of the reading
displayed on the front panel. The selected channel is a1so
the one that will be affected by most other devicc-
dependent commands. In general, those comnvmds which
have front panel equivalents (for example, scan rate and
range) can be programmed separately for each channel.
Those commands which are exclusively associated with
bus operation (for example, SRQ mode and terminator)
affect both channels simultaneously regardless of the
selected channel.
4-43