Agilent Technologies N6700B, User Manual

Page: 165 / 206

Using the Digital Port Appendix C
Series N6700 User’s Guide 165
Fault/Inhibit System Protection
The following figure illustrates some ways that you can connect the
Fault/Inhibit pins of the connector.
As shown in the figure, when the Fault outputs and Inhibit inputs of
several mainframes are daisy-chained, an internal fault condition in
one of the mainframes will disable all of them without intervention
by either the controller or external circuitry.
You can also connect the Inhibit input to a manual switch that will
short the Inhibit pin to common whenever it is necessary to disable
all output channels in the mainframe. You can also use the Fault
output to drive an external relay circuit or signal other devices
whenever a user-definable fault occurs.
Clearing a System Protection Fault
To restore all instruments to a normal operating condition when a
fault condition occurs in a daisy-chained system protection
configuration, two fault conditions must be removed:
1. The initial protection fault or external Inhibit signal.
2. The subsequent daisy-chained fault signal (which is sourced
by the Inhibit signal).
NOTE
Even when the initial fault condition or external signal is removed, the Inhibit
fault signal is still active and will continue to shut down the outputs of all the
mainframes.
To clear the daisy-chained Inhibit signal, you must turn the Inhibit
input off as explained under "Inhibit Input" in the next section.
If the operating mode of the inhibit input is Live, turning off the
Inhibit input on any ONE mainframe will break the fault chain for the
entire system. To re-enable the fault chain, re-program the same
Inhibit input to Live mode.
If the operating mode of the inhibit input is Latched, the Inhibit input
must be turned-off on ALL mainframes individually. To re-enable the
chain, the Inhibit input on each mainframe must be re-programmed
to Latched mode.
Panic
switch
INH
Common
INH
Input
FLT INH
1 2 3 4 5 6 7
I 1 2 3 4 5 6 7
I
1 2 3 4 5 6 7
I
FLT INH FLT INH
+ - + -
+ -