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489 GENERATOR MANAGEMENT RELAY – COMMUNICATIONS GUIDE
CG.3.3 Event Recorder
The 489 event recorder data starts at address 3000h. Address 3003h is the ID number of
the event of interest (a high number representing the latest event and a low number
representing the oldest event). Event numbers start at zero each time the event record is
cleared, and count upwards. To retrieve event 1, write ‘1’ to the Event Record Selector
(3003h) and read the data from 3004h to 30E7h. To retrieve event 2, write ‘2’ to the Event
Record Selector (3003h) and read the data from 3004h to 30E7h. All 256 events may be
retrieved in this manner. The time and date stamp of each event may be used to ensure
that all events have been retrieved in order without new events corrupting the sequence of
events (event 0 should be less recent than event 1, event 1 should be less recent than event
2, etc.).
If more than 256 events have been recorded since the last time the event record was
cleared, the earliest events will not be accessible. For example, if 300 events have been
recorded (that is, the total events since last clear in register 3002h is 300), events 44
through 299 maybe be retrieved. Writing any other value to the event record selector
(register 3003h) will result in an “invalid data value” error.
Each communications port can individually select the ID number of the event of interest by
writing address 3003h. This way the front port, rear port and auxiliary port can read
different events from the event recorder simultaneously.
CG.3.4 Waveform Capture
The 489 stores up to 64 cycles of A/D samples in a waveform capture buffer each time a
trip occurs. The waveform capture buffer is time and date stamped and may therefore be
correlated to a trip in the event record. To access the waveform capture memory, select
the channel of interest by writing the number to the Waveform Capture Channel Selector
(30F5h). Then read the waveform capture data from address 3100h-31BFh, and read the
date, time and line frequency from addresses 30F0h-30F4h.
Each communications port can individually select a Waveform Channel Selector of interest
by writing address 30F5h. This way the front port, rear port and auxiliary port can read
different Waveform Channels simultaneously.
The channel selector must be one of the following values:
VALUE
SELECTED A/D SAMPLES
SCALE FACTOR
0
Phase A line current
500 counts equals 1
×
CT primary
1
Phase B line current
500 counts equals 1
×
CT primary
2
Phase C line current
500 counts equals 1
×
CT primary
3
Neutral-End phase A current
500 counts equals 1
×
CT primary
4
Neutral-End phase B current
500 counts equals 1
×
CT primary
5
Neutral-End phase C current
500 counts equals 1
×
CT primary
6
Ground current
500 counts equals 1
×
CT primary
or 1A for 50:0.025
7
Phase A to neutral voltage
2500 counts equals 120 secondary volts
8
Phase B to neutral voltage
2500 counts equals 120 secondary volts
9
Phase C to neutral voltage
2500 counts equals 120 secondary volts
