Can the I/O ports be used to signal that an alarm value has tripped?
No. The I/O ports provide a steady 5 volt output via a pull-up resistor that is usable for detecting a dry contact closure (such as a door sensor or water sensor). When an outside power source (0-5vdc) is attached, the input is read out on a 0-99 scale with 0 indicating 0 volts and 99 indicating 5 volts.