A–6 PQM POWER QUALITY METER – INSTRUCTION MANUAL
EVENT RECORDER APPENDIX A: APPLICATION NOTES
•Vbc (high)
•Vbc (low)
•Vbc THD
•Vbn (high)
•Vbn (low)
•Vbn THD
•Vca (high)
•Vca (low)
•Vcn (high)
•Vcn (low)
•Vcn THD
ACCESS TO EVENT RECORDER INFORMATION:
There are two ways to access Event Recorder Information:
• Access only the Records and data you wish to view
• Access the entire Event Record.
The Event Recorder is indexed by Event Number (1 to 40). To access a specific Event,
the Event Number must be written to the PQM memory map location 12C0h. The data
specific to that Event can be read starting at memory map location 0AE0h. The specific
Event Number must be known to read the Event Recorder in this fashion. However, this
Event Number is usually not known and the entire Event Record must be read. The eas-
iest way to do this is to read the PQM Memory Map location 0AD0h (Total Number of
Events Since Last Clear) and loop through each Event Number indicated by the value
from 0AD0h, reading the associated data pertaining to each Event. This requires from
1 to 40 serial reads of 170 bytes each. Once this data is obtained, it can be interpreted
based upon the format of each value as described in Section 7.3: Modbus Memory Map.
It is important to note that some memory map parameters are 32 bits (4 bytes) long
and require 2 registers to contain their value, one for the two high bytes and one for
the two low bytes.
Courtesy of NationalSwitchgear.com
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