RFC-1 Advanced Operation page 6.26
6.6 Telemetry Alarms
Incorrect use of the following information can cause unexpected or undesirable behavior. We
strongly recommend that you understand the basic operation of the RFC-1 and the specifics of
the installation before continuing. Please read the documentation above that describes the
Advanced Programming Mode before continuing if you have not done so already.
There are 8 telemetry alarms in the RFC-1. Each alarm can be programmed to monitor any physical channel from
channel 00 to 63. It is also possible for two alarms to monitor the same physical channel such as when a transmitter
operates at two different power levels. In these cases only one alarm is usually active at a time, the other alarms are
blocked so that they do not trigger at inappropriate times of day.
In response to an out-of-tolerance alarm condition, the RFC-1 can be programmed to call station personnel and
report the problem or to log a set of telemetry readings or to try and take corrective actions or even a combination of
these. The default response is to call station personnel and report the condition. Programming the system to make
corrections requires thorough knowledge of the installation and the devices. In most cases calling to report the
condition and/or logging readings is sufficient.
When an alarm condition is detected an action sequence is triggered. The alarm specifies the condition to watch for
such as the channel number and the telemetry limits. It points to an action sequence that will execute when the
alarm limits are exceeded. In the factory settings all alarms trigger a default action sequence that has one
instruction—call all the available telephone numbers to report the alarm.
It is easy to reprogram an alarm to trigger a different action sequence if a different response is desired. The action
sequence can contain any of the commands discussed in section 6.5 of this document.
6.6.1 Telemetry Alarm Programming
The eight telemetry alarms in the RFC-1 are designated Alarm A-H. Each alarm must be programmed with a channel
number, upper and lower telemetry limits, an action sequence to trigger and a trigger rule. There are 12 memory
addresses that store the data for each alarm.
• the first two memory locations identify the telemetry channel to monitor
• the third memory location identifies the trigger rule for the alarm
• the fourth memory location stores the number of the action sequence that is triggered
• the rest of the memory locations store upper and lower limits of four digits each
The programming address table in Appendix A provides a list of all the memory address and their functions. Alarms
A-H occupy memory addresses 0852-0947 in the table.
6.6.2 Channel Number
As mentioned above, there are 8 telemetry alarms in the RFC-1. Each alarm can be programmed to monitor any
physical channel’s telemetry input from channel 00 to 63. When programming the channel number in the alarm, the
first digit of the channel number is programmed at the first memory address and the second digit of the channel is
programmed at the second address. Program the first address with 0 if the channel number is less than 10.
Unused alarms are set to monitor channel number 64. This channel cannot exist so the alarm is disabled.
Each alarm can monitor only one telemetry channel but two alarms (or more) can monitor the same channel. This is
useful in situations such as a transmitter that operates at multiple power levels. In these cases only one alarm is
usually active at a time, the other alarms are blocked so that they do not trigger at inappropriate times of day.
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