RFC-1 Advanced Operation page 6.21
6.5.7 Conditional Execution
There are no instructions in the RFC-1 action sequences for performing loops or making complex decisions. These
kinds of functions are simply beyond the capabilities of the available memory and processing power. However, there
are some instructions that can be used to perform simple conditional behavior.
Stop execution and recheck telemetry
This instruction stops execution of the action sequence and rechecks the telemetry on the channel
that triggered the alarm. If the alarm condition has cleared, the action sequence terminates
immediately. If the alarm condition still exists, the action sequence starts over from the first step but
does not stop to check telemetry again. Instead, it continues to the next step in the action sequence
after the 8-14 instruction. Use only in an action sequence that is triggered by a telemetry alarm.
A common use for this instruction is to stop the RFC-1 from calling with an alarm when a telemetry input briefly
fluctuates out of tolerance. A short delay is inserted at the beginning of the action sequence to allow the device time
to self-correct. Then the 8-14 instruction is used and then the alarm dialing instruction is used.
For example, suppose the telemetry input on channel 02 is a small DC voltage that is proportional to the audio input
to a transmitter. An alarm is programmed to monitor channel 02 so that when this voltage drops below a certain
point, a call is made to alert personnel of an audio failure. Even with a large capacitor it may be normal for this
voltage to briefly drop below the alarm threshold during extended quite passages. In this case an alarm might trigger
because input falls out of tolerance. But by the time the RFC-1 alerts station personnel it is likely that the quite
passage is done and everything is normal. It will appear to be a false alarm.
The 8-14 instruction can be used to avoid the above situation. A new action sequence will be programmed and,
keeping with the example, the alarm that monitors channel 02 will be programmed to trigger the new action
sequence. The action sequence consists of: a short delay of 5 seconds with the instruction 8-2 (from section 6.5.3),
then the 8-14 instruction, then the typical dialing instruction, 9-0. When triggered, the action sequence will pause for
5 seconds giving the audio level time to recover. The 8-14 instruction will cause channel 02 to be rechecked. If it is
back in limits the sequence terminates. If it is still out of limits the action sequence will restart. The delay repeats, the
8-14 is ignored on the second pass and then the dialing instruction executes.
Inhibit new telemetry reference scan upon completion of the action sequence
The RFC-1 normally records a new set of reference readings at the end of an action sequence. This
stops the system from triggering the same alarm repeatedly. Placing this instruction as the final step
of an action sequence suppresses this telemetry reference scan.
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