One-Shot Triggering - Keithley 6517B User Manual

Section 5: Remote Operation
PRINT reading$
'Switch to current and take reading
CALL SEND(27, "func 'curr:dc';:read?", status%)
reading$ = SPACE$(80)
CALL ENTER(reading$, length%, 27, status%)
PRINT reading$
'Switch to 2-wire ohms and take reading
CALL SEND(27, "func 'res';:read?", status%)
reading$ = SPACE$(80)
CALL ENTER(reading$, length%, 27, status%)
PRINT reading$

One-shot triggering

Older instruments generally have two types of triggering: one-shot and continuous. In one-shot,
each activation of the selected trigger source causes one reading. In continuous, the instrument is
idle until the trigger source is activated, at which time it begins taking readings at a specified rate.
Typical trigger sources for non-SCPI instruments are:
• IEEE-488 talk
• IEEE-488 Group Execute Trigger (GET)
• "X" command
• External trigger (rear panel BNC)
Arming the instrument to respond to triggers is implicit in the non-SCPI instruments. Simply
sending a command to a non-SCPI instrument to change any of the trigger controls causes the
instrument to arm itself for triggers.
The SCPI trigger model implemented in the Model 6517B gives you:
• Explicit control over the trigger source (the TRIGger subsystem)
• A two-level control for arming the instrument for triggers
• A way to completely disable triggers
Changing any of the settings in the TRIGger subsystem does not automatically arm the Model
6517B for triggers.
The following program sets up the Model 6517B to take one reading each time it receives an
external trigger pulse.
'Example program that demonstrates one-shot external triggering
'For QuickBASIC 4.5 and KPC-488.2/CEC interface card.
'Edit the following line to where the QuickBASIC
'libraries are on your computer
'$INCLUDE: 'c:\qb45\ieeeqb.bi'
'Initialize the interface as address 21
CALL initialize(21, 0)
'Reset controls in INIT, ARM;LAY1, ARM:LAY2, and TRIG subsystems
'and put trigger model in IDLE state
CALL SEND(27, "*rst", status%)
CALL SEND(27, "trig:sour ext;coun inf", status%)
'start everything
CALL SEND(27, "init", status%)
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Model 6517B Electrometer User's Manual
6517B-900-01 Rev. A / Jun 2008