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Chapter 4 Digital I/O Functionality
NI 1450 Series Compact Vision System User Manual 4-10 ni.com
Disabling Shutdown Mode
To disable Shutdown mode once it is enabled, remove Shutdown mode
from the software script and reset the NI 1450. To reset the system, press
the RESET button on the NI 1450 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 1450 to operate
normally.
Watchdog
The watchdog timer is a software configurable feature that can monitor
software on the NI 1450 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 to take one of the following actions when it
expires:
• Indicator Only—This option sends the expiration signal back to the
development machine through software. True indicates an expired
watchdog timer, and False indicates an unexpired watchdog timer. The
expiration signal that indicates an expired watchdog continues to assert
until the watchdog is disarmed. Disarming the watchdog resets the I/O.
Caution Use the Indicator Only option only to test the watchdog. If software becomes
unresponsive, it cannot be relied upon to send notification to the host.
• TTL Output 0—This option outputs a signal on TTL Output 0. A High
on TTL Output 0 indicates that the watchdog has expired, and a Low
indicates that it has not expired. If the watchdog timer has expired, the
expiration signal will continue to assert until the watchdog is disarmed.
Note LabVIEW RT supports all watchdog timer options. Vision Builder AI supports only
the Indicator Only and TTL Output 0 options.
• System Shutdown—This option halts the NI 1450 operation and turns
the POWER OK LED red. If Shutdown mode is enabled, the outputs
go to the user-defined shutdown states.
Table 4-4 summarizes how user configuration affects the shutdown
condition.