Keithley 2000, User Manual, Page: 62 / 280

Trigger operations
The following paragraphs discuss front panel triggering, the programmable trigger delay, the
reading hold feature, and external triggering.
Trigger model
The flowchart of Figure 3-2 summarizes triggering as viewed from the front panel. It is called
a trigger model because it is modeled after the SCPI commands used to control triggering. Note
that for stepping and scanning, the trigger model has additional control blocks. These are de-
scribed in “Scan operations” later in this section.
Idle
The instrument is considered to be in the idle state whenever it is not performing any mea-
surements or scanning functions. From the front panel, the unit is considered idle at the end of
a step or scan operation when the reading for the last channel remains displayed. To restore trig-
gers, use the SHIFT-HALT keys.
Once the Model 2000 is taken out of idle, operation proceeds through the flowchart.
Control source and event detection
The control source holds up operation until the programmed event occurs and is detected. The
control sources are described as follows:
• Immediate — With this control source, event detection is immediately satisfied allowing
operation to continue.
• External — Event detection is satisfied for any of three conditions:
• An input trigger via the Trigger Link line EXT TRIG is received.
• A bus trigger (GET or *TRG) is received.
• The front panel TRIG key is pressed. (The Model 2000 must be taken out of remote
before it will respond to the TRIG key. Use the LOCAL key or send LOCAL 716 over
the bus.)
Idle
Control
Source
Immediate
External
Event
Detection
Delay
Device
Action
Output
Trigger
Figure 3-2
Front panel trig-
gering without
stepping/scanning
3-8 Measurement Options