RFC-1 Advanced Operation page 6.23
In this example, the RFC-1 has been programmed to make the power changes automatically. At the appropriate
times of day the RFC-1 will execute an action sequence activating relays as needed to change the transmitter power.
When the sequence terminates a new reference reading is made for the alarms. If for some reason the transmitter
does not change power, the RFC-1 will record the current reading as the reference and it will be considered normal
even if it is out-of-tolerance. What is needed is a mechanism to verify that the transmitter made the power change
and is within the appropriate limits.
The solution requires a few things to happen in sequence. First, the block on the low power alarm must end. This
occurs automatically as a function of time. Just make sure the alarm block ends before the power change occurs.
Next, the power change action sequence executes. Following the relay commands to change the transmitter power,
the action sequence has the instruction 10-X selected from the table above. The instruction to use depends on which
alarm is monitoring the telemetry channel. For this example, Alarm B is monitoring the power channel at nighttime
power so the instruction is 10-2 for alarm B.
With the addition of the 10-2 instruction the system verifies the power change on the first alarm scan after the power
change occurs. The 10-X instructions effectively enable or activate the specified alarm by setting the channel reading
within alarm limits. The true status of the system is determined on the next alarm scan and the alarm will trigger if the
channel reading is out of limits. The alarm can call station personnel to alert that the transmitter power did not
change so that the change can be made manually.
Similar behavior can be used to verify that tower lights have turned on in the evening. In most cases the tower lights
are controlled by an automated system so the action sequence only has the appropriate 10-X instruction without any
relay commands. Otherwise the example is the same. Tower light alarms are typically blocked during the day so first
the alarm block must expire. Then a timed action sequence executes the 10-X instruction. The next alarm scan
checks the tower light status and calls personnel if needed.
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