1257 User Manual
Advanced SCPI Operations 7-16
EADS North America Defense
Test and Services, Inc.
©
2001
scan list is deleted.
The present scan list may be deleted using the command
SCAN:DELETE command.
The presently defined scan list may be read using the SCAN?
command. For example, if the scan list shown for the example
above is presently defined, the query:
SCAN?
will generate the reply:
(
@1(323),1(0:2),1(8:5),example,1(0),
state14,1(224))
The reply will NOT include module names, even if the SCAN
command used to define the list included module names. Module
numbers are always used when replying to the SCAN? query.
Advance
Verification
Features
In some applications, it may be desirable for the reason of
reliability to confirm that switches are actually closed or open
based on the commanded state of the system. The 1257 provide
the user with capabilities to detect certain types of switching
failures.
From the standpoint of the 1257, switching failures fall into one of
two classes – detectable and undetectable. An example of an
undetectable failure is where a relay contact has welded closed
through misuse. In this example, the relay coil voltages will verify
properly even though the contact has suffered permanent damage.
There is no easy way to detect this condition without invasively
monitoring the switched-side of the relay. This obviously would
defeat the isolation characteristics of a relay.
The other class of failures – those that are detectable – include coil
and driver failures. The 1257 switching system offers two methods
for identifying and locating these problems.
Confidence Mode
The 1257 supports an operational mode that performs a high-level
system-wide verification. When Confidence Mode is enabled, the
1257 checks the status of all switches after it closes or opens any
of them. The syntax for the command is shown below:
[:ROUTe]
:MONitor
[:STATE] { ON | 1 | OFF | 0 }
If any relay is not in the correct state and Confidence Mode is
