Chapter 3
Digital I/O Functionality
©
National Instruments Corporation
3-11
NI CVS-1450 Series User Manual
Disabling Shutdown Mode
To disable shutdown mode once it is enabled, remove shutdown mode from
the software script and reset the NI CVS-1450 device. To reset the system,
press the
RESET
button on the NI CVS-1450 device front panel for at least
two seconds.
Note
For prototyping when equipment is unavailable, you can wire from Viso to
ISO Input 11 to simulate external equipment that indicates to the NI CVS-1450 device
to operate normally.
Watchdog Timer
The watchdog timer is a software configurable feature that can monitor
software on the NI CVS-1450 device and take action if the software is
unresponsive. The millisecond counter on the watchdog timer is
configurable up to 65,534 ms, in 1 ms increments, before it expires.
Configure the watchdog timer to take one of the following actions when it
expires:
Caution
Use the
Indicator Only
option
only
to test the watchdog timer. If software
becomes unresponsive, it cannot be relied upon to send notification to the host.
•
Indicator Only
—This option sends the expiration signal back to the
development machine through software.
True
indicates an expired
watchdog timer.
False
indicates an unexpired watchdog timer. The
expiration signal that indicates an expired watchdog timer continues to
assert until the watchdog timer is disarmed. Disarming the watchdog
timer resets the I/O.
•
TTL Output 0
—This option outputs a signal on TTL Output 0. A
High
on TTL Output 0 indicates that the watchdog timer has expired.
Low
indicates that it has not expired. If the watchdog timer has
expired, the expiration signal continues to assert until the watchdog
timer is disarmed.
•
System Shutdown
—This option halts the NI CVS-1450 device
operation and turns the
POWER OK
LED red. If shutdown mode
is enabled, the outputs go to the user-defined shutdown states.
Table 3-4 summarizes how user configuration affects the shutdown
condition.
Note
The
Watchdog Timer
feature is not supported by Vision Builder for Automated
Inspection.
