Remote Programming - Scanning; Trigger Model - Keithley 2750 User Manual

7-26 Scanning
Remote programming — scanning
NOTE

Trigger model

The trigger model for bus operation is shown in
front panel SCAN operation, with the following significant differences:
Idle — The instrument goes into the idle state (measurements halted) after the last scan
channel is measured. For front panel operation, the instrument stays in idle until the next
scan is started. For bus operation, the instrument will not stay in idle unless continuous ini-
tiation is disabled. There are two commands to disable continuous initiation:
INITitate:CONTinuous OFF
*RST
The instrument will remain in idle until it receives an initiate command. Typical com-
mands to initiate one scan cycle include:
INITiate
READ?
More information on using these commands is provided by Reference c that follows
Table
Control sources — For bus operation, there are two additional control sources: Bus and
Manual. For the Bus control source, scan operation is controlled by bus triggers (i.e.,
*TRG) or by using the TRIG key. For the Manual control source, event detection is con-
trolled solely by the TRIG key. Note that the instrument has to be in local in order to use
the TRIG key. The LOCAL key takes the instrument out of remote.
Trigger and sample counters — For front panel SCAN operation, the number of chan-
nels in the scan list and the programmed reading count automatically sets the trigger and
sample counters. For remote operation, these two counters are set by the
TRIGGer:COUNt and SAMPle:COUNt commands.
NOTE
Scanning examples (remote programming and front panel operation) are pro-
vided at the end of this section.
' Initiate one scan cycle.
' Initiate one scan cycle and request "sample" readings.
7-1.
To set sample count >1, continuous initiation must be disabled (see "Idle").
Note that only sample count readings are stored in the buffer. See
detailed information on the trigger model.
Model 2750 Multimeter/Switch System User's Manual
Figure 7-2. Bus operation is similar to
' Disable continuous initiation.
' Restore *RST defaults.
Section 8 for