Agilent Technologies Series N6700 User Manual page 89

Couple Output Protection
Output Watchdog Timer
Series N6700 User's Guide
Factors that influence how long the settings change or output load
change may last include: difference between old output value and
new output value, the current limit setting, and the load capacitance
in CV mode or load inductance in CC mode. The delay required must
be determined empirically; the power module programming-response
time characteristics may be used as guidelines.
Note that the time it takes the output to go into CC mode varies -
depending on the magnitude of the over-current condition compared
to the current limit setting. For example, if the over-current is only
slightly greater than the current limit setting, it may take several tens
of milliseconds, depending on the power module type, for the output
to set the CC status bit. If the over-current is significantly greater
than the current limit setting, it may only take a few milliseconds or
less, depending on power module type, for the output to set the CC
status bit. To determine when the output will shut down, you must
add the time it takes for the CC status bit to the over-current
protection delay time. If the over-current persists beyond the sum of
these two time intervals, the output will shut down.
Protection coupling lets you disable all output channels when a
protection condition occurs on a single output channel. To couple
output protection:
Front Panel:
Select Protect\Couple.
Check the Enable Coupling box and
press Select.
The output watchdog timer causes all outputs to go into protection
mode if there is no SCPI I/O activity on the remote interfaces (USB,
LAN, GPIB) within the user-specified time period. Note that the
watchdog timer function is NOT reset by activity on the front panel
or when using the Web server – the outputs will still shut down after
the time period has elapsed..
After the time period has expired, the outputs will be disabled, but
the programmed output state is not changed. The PROT bit in the
status questionable register as well as the PROT indicator on the
front panel will be set.
The watchdog delay can be programmed from 1 to 3600 seconds in 1
second increments. As shipped from the factory, the watchdog timer
is set to disable the outputs 60 seconds after all IO activity has
ceased.
The watchdog state and delay settings are volatile, but can be saved
and recalled as part of the instrument state. A watchdog protect can
be cleared as described under "Clear Output Protection Functions".
Operating the Power System 4
SCPI Command:
To enable output protection coupling:
OUTP:PROT:COUP ON
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