RFC-1 Advanced Operation page 6.28
6.6.5 Upper and Lower Limits
The upper and lower limits specify the range of acceptable telemetry values for a channel. Limits are programmed
using 4 digits. If the telemetry channel reading has a decimal point, ignore the decimal but keep the digits following
the decimal. Digits are critical. Decimal points and unit words are not critical. If the reading is not 4 digits long, add
zeros to the left until the reading has 4 digits.
For example, to program an upper limit of 105.0 percent when the normal reading is 99.8 percent, set the upper limit
to 1050. To program a lower limit of 90 percent when the normal reading is 99.8 percent, set the lower limit to 0900.
In come cases only one limit is considered critical. The default trigger rule can be used. Set the alarm limits to
compensate.
• If only the upper limit is critical, set the upper limit as necessary and set the lower limit to 0000
• If only the lower limit is critical, set the lower limit as necessary and set the upper limit to 9999
Setting alarm values on status channels causes some confusion but it is really quite easy. Status channels are
treated as numbers internally. The scale is the same as the factory default setting, 0000 to 2040, and the trip point is
mid-scale, 1020. When monitoring a status channel, typically only one limit is considered critical and the other is
usually ignored. The following general rules work well in most cases.
• To trigger when the input goes from low to high, set the upper limit to 1500 and the lower limit to 0000
• To trigger when the input goes from high to low, set the upper limit to 9999 and the lower limit to 0500
These rules refer to the voltage sample on the telemetry input; not the resulting channel reading. Status channel
readings can be inverted in software. The channel reading may not be an accurate indicator of the voltage sample.
6.6.6 Enabling and Disabling Telemetry Alarms
There are three ways to enable and disable telemetry alarms in the RFC-1.
1. Enter commands manually to enable or disable a single alarm or the entire alarm system.
2. Use alarm blocks to disable one or more alarms as a function of month, day and time of day.
3. Selectively enable and disable alarms with commands in an action sequence.
The telemetry alarm system can be enabled and disabled with a single command, 82, in the RFC-1. The RFC-1 will
deliver the current telemetry alarm system status then it will say “push # to reprogram”. If you press the # key, the
RFC-1 responds with “enter one digit”. Press 0 to disable the telemetry alarm system or 1 to enable the telemetry
alarm system. All other entries are invalid.
The RFC-1 ships from the factory with the telemetry alarm system disabled. You must enable it for the RFC-1 to
scan for telemetry conditions.
In the default settings all alarms are programmed to monitor channel 64. This effectively disables the alarm. Enable
an alarm by programming a valid channel number and upper and lower limits. The commands 90-97 are provide the
easiest method for reading and adjusting alarm values. See Section 5 of this manual for details on these commands.
Enabling and disabling telemetry alarms in an action sequence is discussed in Section 6.5 of this manual. That
section covers all of the commands that can be used in an action sequence.
To Next Page
Loading...
Need help?
General
