ICS PCI-WDT50 Series, Product Manual

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Manual Number: 00650-144-1 Page 7
Additional Features On PCI-WDT501
Computer Power Monitor
The three computer power supplies (+5V, +12V, and -12V) are monitored. If one or more of those
voltages are more than ±6% outside of their nominal values, then two bits of a Status Register
indicate whether there is an overvoltage or an undervoltage. In addition, an interrupt request can be
generated.
Computer Temperature Monitor
This feature monitors ambient temperature inside the computer chassis. The temperature monitor
circuit compares the output of an LM334 temperature sensor with a preset DC voltage level. The
output of the comparator circuit can be read at a bit location of the Status Register and, also, can
cause an interrupt request if that temperature exceeds the factory preset limit (50°C).
Computer Temperature Measurement
An onboard 8 bit A/D converter provides means for a software read of the measured temperature.
Resolution is to approximately 0.7
O
F.
Change of State
Differential digital inputs are accepted through pins 17 and 18 (ISOIN0). Pins 19 and 20 (ISOIN1)
are opto-isolated and reported in the Status Register. The change-of-state also generates an IRQ
interrupt request.
Fan Speed
This function is usable only in computers which use fans that have a tachometer output. If fan
speed falls to unsafe levels (i.e., if the tachometer output falls to less than 50pps), an interrupt
request is generated.
Buzzer
The buzzer is under software control and can be turned on by programming a “write” to Base
A 4 or off by programming a “write” to Base A5 if counter 2 is configured in mode
1. Configuring counter 2 in mode 0 will defeat the buzzer entirely. (See Programming, Section 5,
for more information.)
Opto-Isolated Outputs
This feature provides an opto-isolated reset signal at pins 4 and 5 (Isolated Reset Output) of the
DB25 connector. An opto-isolated inverse of the reset signal is also provided across pins 6 and 7
(Isolated NOT Reset Output) of the same connector.
This option deletes the opto-isolated Reset output capability and replaces it with capability to
provide outputs under computer control. When this option is installed, one or both of these outputs
may be computer controlled. The option is enabled by a write to base F. To activate the