A-18 MIB High Impedance Bus Differntial Relay GEK-106426B
A.6 OSCILLOGRAPHY APPENDIX A
A
A.6OSCILLOGRAPHY
Oscillography reading operation consists of four steps:
1. Send an Open Oscillography command (in a similar way as for operation selection). The code to open
oscillography is 11H.
2. The module will prepare the information to be sent and when it is ready it will send the ModBus response. If
there is no oscillography stored, the module will respond with a Not Acknowledge code (error #7).
3. When the oscillography opening command has been executed, the registers with the information will be
available to read. There are three blocks of information:
3.1. Samples buffer: analog (currents and/or voltages) and digital channels.
3.2. Trigger report: RMS values of analog channels and active table in the moment of the oscillography trigger
3.3. Configuration: additional data for the COMTRADE format files, such as: date and time, sampling rate,
number of samples, line frequency, oscillo number.
The oscillography buffer starting addresses and lengths are defined in the memory map of each module. See attached
table for a reference.
4. Send a Close Oscillography command (in a similar way as for operation confirmation). The code to close
oscillography is 12H. The information remains in memory and it is not necessary to delete it because only one
oscillography can be stored at a time and the memory will be overwritten when a new one is generated.
Same as with events, the size of each oscillography register will be different depending on the module type, and the
memory addresses of oscillography buffers may also vary with the firmware version as detailed in the following table. The
addresses shown are only orientative as they can change with module and firmware version. Check the actual memory
map of every module with EnerVista MII Setup program to ensure that the addresses used are the correct ones.
MODULE MIB
Firmware version 1.00
Samples buffer start 07D4
Sample record size (bytes) 18
Length of samples buffer 3456
Trigger Report start 1554
Trigger Report length 18
Configuration start 1566
Configuration length 16
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