Electro Industries Shark 200 Installation & Operation Manual page 248

Present State (snippet)
PQ Va Vb
Record Surge Surge
10 x
Only the first 3 bits are being shown for the present states and event channel byte
arrays (along with their timestamps) in the example provided and from the snippet
above, three different example scenarios can be observed. The following example
explanations serve only to show the behavior of the two byte arrays as well as show
how to calculate the duration by determining the Out and Return PQ records in the
given situations.
The surge occurring on Channel Vb is an example of a normal PQ event where both
the beginning (Out) and end (Return) can easily be determined. It is shown to have
surged starting from PQ record 2. All the subsequent PQ records continued to surge
on the same channel until reaching PQ record 8. Looking at the event channel byte
array, a change had occurred on both PQ records 2 and 8. Using the information from
both byte arrays, it is easy to see that PQ record 2 is the Out Record and PQ record 8
is the Return Record. Thus the PQ event duration is simply the timestamp difference
between those two records (e.g., 6 seconds).
The following examples describe error conditions which may occur in the PQ records
when PQ trigger conditions are missed. For example, if a surge comes back into limit
while the meter is resetting, it may not record the return to normal event.
Channel Va shows an example of a special case where the surge on PQ record 3 is not
recorded under the Event Channel for that same record. This shows a discrepancy
where a PQ record or numerous PQ records may be missing before the entry of PQ
record 3. Under these situations, it may not be possible to find the Out Record (the
beginning of a PQ event). This can be detected by an Out condition in the Present
states table, with no matching change in the Event Channel table.
Channel Vc shows an example of a special case where the surge on PQ records 4-5 do
not show a return to normal condition in the Event Channel in record 6. This shows a
discrepancy where a PQ record or numerous PQ records may be missing between
records 5 and 6. Under these situations, it may not be possible to find the Return to
Normal Record (the end of a PQ event). This can be detected by an Out condition in
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Vc
Timestamp
Surge
2013/04/01
02:10:23
PM
B: Modbus Map and Retrieving Logs
Event Channel (snippet)
PQ Va Vb
Record Surge Surge
10 x
#
Doc E149701
Vc
Timestamp
Surge
2013/04/01
02:10:23 PM
B-64