User manual

Front Panel Operation
2001-900-01 Rev. K/ August 2010 3-65
2. To program for a different count (1 to 99999), use the
cursor keys ( and ) to select the digits, and the
RANGE  and  keys to increment and decrement
the digits.
3. With desired count value displayed, press ENTER. The
display returns to the SETUP arm layer menu.
CONTROL
Use this menu item to enable or disable the source bypass.
The source bypass is used to bypass the arm event on the first
pass through the arm layer. With the SETUP arm layer menu
displayed, select this menu item by placing the cursor on
CONTROL and pressing ENTER. The following menu is
displayed:
TRIGGER CONTROL
SOURCE ACCEPTOR
SOURCE: With this selection, the source bypass is enabled.
The arm event will be bypassed on the first pass through the
arm layer. This allows operation to proceed into the scan
layer without having to wait for the programmed event.
ACCEPTOR: With this selection, the source bypass is dis-
abled.
3.7.5 Halting triggers
The Halt option of the CONFIGURE TRIGGER menu is
used to disarm the instrument and place it in the idle state.
You can press the TRIG key to resume front panel triggers.
Perform the following steps to halt triggers:
1. Display the CONFIGURE TRIGGER menu by pressing
the CONFIG key and then the TRIG key.
2. Use the cursor keys ( and ) to place the cursor on
HALT and press ENTER to display the following tem-
porary message:
TRIGGERS HALTED
Press TRIG key to resume.
3.7.6 External triggering
The Model 2001 has BNC connections on the rear panel for
external triggering (see Figure 3-23). The EXTERNAL
TRIGGER INPUT jack allows the Model 2001 to be
triggered by other instruments. The METER COMPLETE
OUTPUT jack allows the Model 2001 to trigger other
instruments.
External trigger
The EXTERNAL TRIGGER INPUT jack requires a falling-
edge, TTL-compatible pulse with the specifications stated in
Table 3-29 (also shown in Figure 3-23):
In general, external triggers can be used as events to control
measure operations. For the Model 2001 to respond to
external triggers, the appropriate layers of trigger model
must be configured for it. Paragraphs 3.7.2, 3.7.3, and 3.7.4
explain how to program the three layers of the measurement.
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TTL high 2 V to 5 V
TTL low  0.8 V
Minimum pulse
width
2 s
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External triggering connectors (BNC)
EXTERNAL
TRIGGER
INPUT
METER
COMPLETE
OUTPUT
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External triggering and asynchronous trigger link input
pulse specifications
Triggers on
Leading Edge
TTL High
(2V-5V)
TTL Low
(≤0.8V)
2µs
Minimum