National Instruments NI CVS-1450 Series User Manual

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Chapter 4
Digital I/O Functionality
© National Instruments Corporation
4-11
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 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 4-4 summarizes how user configuration affects the shutdown 
condition.
Overheat
Operating the CVS-1450 device outside of its temperature specifications 
may cause the CVS-1450 device to overheat. Refer to Appendix B
, for temperature specifications.
In the event of an overheat, all CVS-1450 device operation halts and the 
POWER OK LED turns red. If Shutdown mode is enabled, the outputs 
go to the user-defined shutdown states.