Racal Instruments 1256E, Руководство пользователя

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1256E User Manual
Racal Instruments
©
2002 Advanced SCPI Operations 8-13
read it. Any delay over 10 milliseconds rounds the delay to the
nearest 10 milliseconds.
Figure 8-2, External Trigger In and External Trigger Out
Using Scan Lists
and External
Trigger Input
A scan list allows you to specify a list of switching commands to be
performed. Once you have defined this list, the 1256 will
automatically sequence through the scan list, executing one
command each time it detects a trigger pulse at the external trigger
input of the SYNC/TRIG connector.
Three types of commands may be entered into a scan list:
•
Close a specific relay
•
Recall a state stored in a non-volatile memory location
•
Break (stop scan list processing)
Scan Lists
The 1256 may be programmed to sequence through a list of
channels. This feature is known as a “Scan List”.
When a Scan List is used, the user defines a list of channels to
operate. Each time a trigger is received by the 1256, the presently
closed channel is opened, and the next channel on the list is
closed. This capability may be used in conjunction with a Digital
Multimeter (DMM) or other measurement device to allow a group
of measurements to be made without having to program the 1256
for each relay operation.
For example, without the Scan List feature, for each DMM reading,
you must:
Trigger In
Trigger Out
Trigger In/Out Electrical Characteristics
Logic levels: TTL
Trigger In Input Impedance: 10 K-ohms
Trigger Out Drive Current: Sink/Source 4 mA