
53
Programming Meter Alarms
Each of the Meters has a high and low alarm
trippoint.
Once programmed, when a meter reading reaches either of these points, a
Command Macro will be run. For example, a meterface can be defined to read temperature from an external sensor. If the measured
temperature exceeds the programmed high level, a Macro will be run. If the temperature drops below the programmed low limit, a
Macro will be run. Of course the same Macro can be programmed for both the high and low points but different macros will generally be
used for each trippoint. The format for programming a meter alarm is:
*2066 alarm number * meter number * alarmtype * trippoint * macro to run *
There are 8 meter alarms, 1 through 8
Meter Number is 1 through 8 (for the ADC channels)
AlarmType determines the action taken by that alarm:
1 - Low Alarm
2 - High Alarm
Trippoint is the value to use for the high or low setting, multiplied by 100 and rounded to the nearest whole value. In our example
above, we defined the meterface to measure temperatures from -35 to +150 degrees. We want our high trippoint to be set to +100
degrees, so we take "100" and multiply by 100 which gives us "10000". This is the number we enter for the trippoint value. If we want to
enter a negative value for the trippoint (for example, -10 degrees), we simply preface the calculated value with a DTMF "A". For
example, we want to set the low trippoint to -10 degrees. -10 x 100 = -1000, so we would enter "A1000" for the trippoint value.
Macro to run is the Command Macro we want to be executed when our alarm trips.
A Practical Example
Let's say that we have a temperature sensor connected to Meter Input 1. We also have the PA power control line connected to Logic
Output 5. Once our meterface is programmed (as shown in the Programming Meter Faces section above), we want to program a Meter
Alarm to put the PA into its low power mode when the sensed temperature rises above 135 degrees. Since our PA control line requires
that it be pulled to ground in order to enter low power mode, we need to turn ON the appropriate logic output and we'll use Command
Macro 22 for this. And since this is our first Meter Alarm definition, we'll use Meter Alarm 1.
First, we program Macro 22 to turn on Logic Output 1
*4002 22 095
Now we program the Meter Alarm itself
*2066 1 * 1 * 2 * 13500 * 22 *
Now, if the sensed temperature rises above 135 degrees, the PA control line will be pulled low. Of course, we'd like a way to put the PA
back into high power mode once the temperature drops back down to a safe temperature. We decide that once the PA temperature
falls back down to 80 degrees, it is safe to put it back into high power mode. We'll use Meter Alarm 2 and use Macro 23 to turn Logic
Output 1 back off.
*2066 2 * 1 * 1 * 8000 * 23 *
When the sensed temperature falls below 80 degrees, the PA will be put back into high power mode.
Содержание RC210
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