Keithley 7002-HD User Manual page 43

4-12 Front Panel Operation Model 7002-HD User's Manual
Idle
The instrument is considered to be in the idle state whenever it is not operating
within one of the layers of the Trigger Model. The front panel ARM indicator is off
when the instrument is in the idle state. While in the idle state, the instrument can-
not perform a scan.
From the front panel, the Model 7002-HD is taken out of the idle state by pressing
the STEP key. When not in the idle state (ARM indicator on) the scanning function
is considered to be enabled.
A scan can be aborted at any time by pressing the OPEN ALL key. The Model
7002-HD will return to the idle state.
Once the instrument is taken out of the idle state, operation proceeds into the arm
layer of the Trigger Model.
Arm layer
In general, the instrument requires an arm event to allow operation to proceed to the
next layer (scan layer). With Immediate arm spacing selected, operation immediately
proceeds to the next layer when the instrument is taken out of the idle state. RESET
and factory defaults set arm spacing to Immediate. With one of the other arm spac-
ing events selected, the instrument waits until the appropriate event occurs.
Operation in the scan layer is similar to operation in the arm layer, except that
spacing is controlled by scan events rather than arm events. A timer is available in
this layer to control scan spacing. When Timer scan spacing is selected, operation
will immediately proceed into the channel layer on the initial pass through the scan
layer. Each additional scan (1 to 9999, or infinite) will not occur until the pro-
grammed timer interval elapses. The timer can be set to an interval from 1 milli-
second to 99999.999 seconds.
The Source Bypass and Output Trigger function in the same manner as the
Source Bypass and Output Trigger in the arm layer. The Source Bypass (if
enabled) will reset (back in effect) after all programmed scans are completed.
RESET and factory defaults set scan spacing to Immediate, scan count to Infinite,
and Scan Trigger Control to Acceptor.
After leaving the scan layer, operation proceeds into the channel layer.
Channel layer
Operation in the channel layer is similar to operation in the scan layer, except that
spacing is controlled by channel events rather than scan events, and the Output
Trigger is always enabled.
When Timer channel spacing is selected, the first channel will be scanned imme-
diately. Each additional channel is then scanned at a rate determined by the pro-
grammed timer interval (1 millisecond to 99999.999 seconds). With Immediate
channel spacing selected, channels will be scanned immediately. The scan rate
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