MEMORY MAP 6. COMMUNICATIONS
6-16
6.5.4
WAVEFORM CAPTURE
The SR469 stores a number of cycles of A/D samples each time a trip occurs in a trace buffer, determined by the setpoint in S1 Prefer-
ences, Trace Memory Buffers. The Trace Memory Trigger is set up in S1 Preferences and this determines how many pre-trip and post-
trip cycles are stored. The trace buffer is time and date stamped and may be correlated to a trip in the event record. 10 waveforms are
captured this way when a trip occurs. These are the 3 phase currents, 3 differential currents, ground current and 3 voltage waveforms.
This information is stored in volatile memory and will be lost if power is cycled to the relay.
To access the captured waveforms, select the waveform of interest by writing its trace memory channel (see following table) to the
Trace Memory Channel Selector (address 30F1h). Then read the trace memory data from address 3100h to 3400h. There are 12 sam-
ples per cycle for each of the cycles. The values read are in actual amperes or volts.
TRACE MEMORY CHANNEL WAVEFORM
0 Phase A current
1 Phase B current
2 Phase C current
3 Differential phase A current
4 Differential phase B current
5 Differential phase C current
6 Ground current
7 Phase A voltage
8 Phase B voltage
9 Phase C voltage
Address 30F8h shows the number of traces taken. To access the latest use the value at address 30F0h. To access more than 1 trace,
reduce this value to access the older traces.
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