Operating instructions

1892 1335 - Orion Radio Modem Operating Instructions - v2.9 / Aug 2009 51
Digital Alarms
Figure 21 - Digital Alarm tab on lower set
Each input can transmit an alarm message back to the Base if certain conditions are met or
exceeded.
A normal digital input must make the transition indicated by the Trigger setting and remain
there for at least the time entered into the Dwell Time box. This alarm can be turned on and
off using the Counter Trip Level box: 0 means off, any other value means on. Dwell time is in
units of 10ms, so for example one minute is represented by 100.
A pulse counting input must count up to the number of pulses entered in the Counter Trip
Level box. Entering 0 in this box turns the alarm off. The Trigger setting indicates the
polarity of pulse which is counted (L to H indicating a positive-going pulse), and the Pulse
Width box specifies the minimum pulse width which will be counted in units of 10ms.
To clear a normal input alarm and transmit a message back to Base, the input must make the
complementary transition and remain there for at least the Dwell Time. Pulse counting input
alarms are automatically cleared when they are read, because their count is reset to zero.
(The target value in the Counter Trip Level box is unaffected.)