Data alarms are integrated directly into the host daemon and have the following two abilities:
- Write critical real-time data to the alarm table when a alarm event is triggered
- Optionally email the alert to any number of recipients
The trip-points at which an alarm is triggered is configurable in the alarmpoints table. The default values should suffice in most cases.
The email option is turned on in the configuration file for the host daemon. Details on this are found in a later section.
Whenever an alarm is tripped, the event is written to the alarm table. The fields are defined as follows:
Field | Description |
call_ssid | The call-ssid of the server |
dtg_local | The local date/time of the event |
dtg_zulu | The UTC (zulu) date/time of the event |
wac_spd | Current average wind speed in MPH |
wac_dir | Current average wind direction in degrees |
wgc_spd | Current gust wind speed in MPH |
wgc_dir | Current gust wind direction in degrees |
pca | Precipitation amount in hundredths of a inch since midnight local time |
pri | Instantaneous precipitation rate in hundredths of an inch per hour. Based on the amount of precipitation that has fallen in the last five minutes. |
prh | Hourly precipitation rate. The amount of precipitation that has fallen in the last 60 minutes. |
p24 | The 24 hour precipitation total. Note that is a true 24 hour figure, not the amount since midnight. |
tcr | Current temperature in degrees Fahrenheit |
bcr | Current barometric pressure in tenths of a millibar |
hcr | Current relative humidity in % |
uvc | for future use |
ecc | Number of EMP (lightning) strikes in the last five minutes |
eqc | Number of EMP (lightning) strikes in the last 15 minutes |
exc | Number of EMP (lightning) strikes in the last 30 minutes |
ehc | Number of EMP (lightning) strikes in the last 60 minutes |
edc | Number of EMP (lightning) strikes since midnight local time |
rca | Current background radiation count in uRoentgens. Field will be empty if there is no background radiation monitor present. |
rha | Hourly background radiation count average in uRoentgens. Field will be empty if there is no background radiation monitor present. |
rda | Background radiation count average since midnight local time in uRoentgens. Field will be empty if there is no background radiation monitor present. |
rmax | Maximum background radiation count detected since midnight local time. Field will be empty if there is no background radiation monitor present. |
ralarm_count | Number of time ralarm_trip has been exceeded since midnight local time. Field will be empty if there is no background radiation monitor present. |
ralarm_trip | uRoentgen level at which a background radiation alarm will be tripped. Field will be empty if there is no background radiation monitor present. |
The alert system features the ability to selectively send email alerts to different parties. This is accomplished by single character entries for each type in the alerts field of the email table.
Aside from being able to specify which parameter will trigger an email, you also specify the format of the email. Two formats are supported: full text and pager.
In the full text mode, all current real-time data collected by the system is formatted in a message and sent to the user. The following is representative of the body of an example message:
Wxn Email Server Alert
DO NOT REPLY (automated message). Click on 'Reply-To' if you need to contact the sysop.
The following parameter(s) tripped this alert: precip
Location: Evansville, IN (Vanderburgh)
Coordinates: 38.03 N, 87.58 W
Date/Time of alert: 2004-07-23 15:05 UTC
Temperature = 72
PRECIP: Total since midnight local time = 0.06"
Total last 24 hours = 1.47"
Instantaneous hourly rate = 0.12"
Hourly Rate = 0.05"
WIND: Gust Dir/Speed: 350 deg @ 4 mph
Avg Dir/Speed: 350 deg @ 1 mph
Barometric Pressure: 30.32" (1012.3 mb)
Humidity = 100%
EMP 5/15/30/60/Day = 0 / 0 / 0 / 0 / 0
Background Radiation Monitor
Current/Hourly/Daily Avgs = 14 / 11 / 11 (uRtgns)
Maximum for the day: 16 uRtgns
Alarm trips for day / Alarm trip-point: 0 / 27 (uRtgns)
*** End Of Message
Because of the size of the message window on the pager itself only the group that tripped the alarm is sent. The location is designated by the 5-digit FIPs code followed by the date/time of occurrence. The next line then uses the field names from the database itself. No decimal points are used in any values. Example:
@18163,05270310z
pca=236,pri=312,prh=83,p24=236
To translate this message, the state is Indiana (18), the county is Vanderburgh (163), the event took place on 27 May 2003 at 0310 UTC (aka zulu time, hence the trailing z). The data is given in the second line: precip since midnight is 2.36", instantaneous rate is 3.12"/hour, there was 0.83" rain last hour, and the total for the last 24 hours is 2.36".
Configuration is implemented in two tables and the wxnhostd.conf file.
Whenever a parameter is exceeded, an entry is made in the alarm table and email is generated (if configured).
Field | Default | Description |
call_ssid | - | Auto-generated by system. Unless the call-ssid of the node has been changed, do not modify. Doing so otherwise will render the alarm feature inoperative. |
prh | 100 | Hourly precipitation rate in expressed in hundredths of an inch. This reflects the actual amount of precipitation that has fallen in the last 60 minutes. The entry will only be made once an hour after the first occurence. Entries will discontinue once the hourly rate is below the threshold for a full 60 minutes. |
p24 | 100 | 24-hour precipitation rate in expressed in hundredths of an inch. This reflects the actual amount of precipitation that has fallen in the last 24 hours. Like the houlry precip rate, this entry will only be made once and then repeat once every 24 hours until the 24 hour totals fall below the threshold for a full 24 hours. |
wgh | 40 | High wind gust expressed in miles-per-hour. Entries will be made whenever this parameter is exceeded (i.e., every five minutes if necessary). |
wah | 40 | High wind average expressed in miles-per-hour. As with gusts, entries will continue to be generated as long as the average is above the threshold. |
thr | 150 | High temperature. If the temperature continues to rise after the initial event, no more entries will be made until the temperature falls below the threshold and then rises above it again. |
tlr | 0 | Low temperature. If the temperature continues to fall after the initial event, no more entries will be made until the temperature rises above the threshold and then falls below it again. |
blr | 982 | Barometer low reading in millibars. The equivalent of the default is 29.00" inches of mercury. If the pressure continues to fall after the initial event, no more entries will be made until the pressure rises above the threshold and then falls below it again. |
ecc | 200 | EMP hit count threshold. Entries will be made whenever this parameter is exceeded (i.e., every five minutes if necessary). |
rad | 27 | Background radiation reading. Entries will be made whenever this parameter is exceeded (i.e., every five minutes if necessary). |
wxnhostd.conf - only entries that apply are shown
Keyword | Type | Default | Description |
EmailAlertEnable | Boolean | n | Enables the server to send email to recipients specified in the email table when an alert condition is detected. |
EmailHost | Text | ? | Required field. This must be an ISP whith whom you have a valid email account. This is the part of the email address that follows the '@' sign. |
EmailFromAcct | Text | ? | Required field. This must be a valid email account "user" name. This is the part of email address that precedes the '@' sign. |
EmailFromName | Text | ? | Optional field. Name of the email 'sender' (not the actual account). This can be an alias or some other identifier if you wish. If not used, leave blank. |
EmailReplyTo | Text | ? | Required field. This is the full email address to whom replies to the automated message will be sent. This is needed in case the recipient needs to verify the data or report a problem to you (the sysop). |
Fill values in this table of those persons you wish to receive email whenever an alert is generated by the system.
Field | Description | ||||||||||||||||
recip | This is the user account name on the destination host. For example, if the address is 'jdoe@myisp.com', jdoe would be placed in this field. | ||||||||||||||||
host | This is the host name of the destination. For example, if the address is 'jdoe@myisp.com', myisp.com would be placed in this field. | ||||||||||||||||
name | This field is used to hold the user's real name. Using the previous example as a starting point, this field could be Jane Doe. | ||||||||||||||||
mtype | This field determines whether a full text message is sent or an abbreviated one suitable for pager displays. The entry consists of a single character, 't' for full text or 'p' for pager format. | ||||||||||||||||
alerts | Determines the type of event that will trigger an email message. The following
table shows which characters to be entered to specify an event message:For example, if you only want to get emailed on wind, hourly precip values and EMP, the field entry shoudl be 'whe' (without the single quotes). If all events are to trigger an email, a single '*' (without the single quotes) should be entered in the field. |