[evla-sw-discuss] Terminology

[Vrcic, Sonja]

Here is how the AMCS Preliminary Requirements defines alert types :

Failure - a non-working state (a +5 VDC monitor point reads 0 VDC)
Warning - out of tolerance state (a +5 VDC monitor point reads +4.7 VDC)
Error - undefined or illegal state (such as if  a hardware device was
commanded to a position outside its operating range) 

In addition, the VCI Protocol Specification defines:
Information - non-fault event that should be reported to M&C System (e.g. a
device has become operational)

I agree that failure and error could be replaced by a single type, however,
in some situations, the distinction between error and failure may be useful.


Note that in addition to alert type the Alert message also reports severity,
which can help the M&C to decide when the alarm bell starts ringing. 

The VCI Protocol Specification defines severity as an integer in the range 0
to 10 (should it be 0 to 15), where 0 is the lowest and 10 is the highest
severity. Lower severity codes (e.g. 0 to 4) are used for debugging
purposes, and are assigned to events that should not be reported  during
normal operation. At any time, the M&C System should be allowed to specify
the severity level of events it is interested in. 

Severity code is used to define significance and scope; there can be a
failure with relatively low severity code and an information with high
severity code. 


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Sonja Vrcic | Tel: (250) 490-4309 | Fax: (250) 493-7767 |
sonja.vrcic at nrc.gc.ca
National Research Council Canada,  P.O. Box 248, Penticton, BC, V2A 6J9
Conseil national de recherches Canada,  B.P. 248, Penticton, CB, V2A 6J9
Government of Canada | Gouvernement du Canada
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