GE Multilin PQM, Инструкция по эксплуатации

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APPENDIX A: APPLICATION NOTES DATA LOGGER IMPLEMENTATION
PQM POWER QUALITY METER – INSTRUCTION MANUAL A–17
Blocks 0 and 1 are reserved for Data Logger Data Interval information. Block 2 contains the
Header information for both Data Logs. The first 32 registers of Block 2 are reserved for
Data Log 1 Header Information, and the remaining 32 registers of Block 2 are reserved for
Data Log 2 Header Information. The first register of Data Log information resides at
Register 1 of Block 3. This leaves 65152 bytes of storage for data.
The location of the first Record in Log 2 will depend upon the Log configuration. Its location
is determined by reading the Log 2 Header value for Log Start Address at location 0AAEh in
the memory map and performing a calculation. The Log Start Address is a value from 0 to
65535 representing the first byte of the first Record within the Data Log memory structure.
Add 1 to this number and then divide this number by 64 (number of Records in a Block).
Then divide this number by 2 (number of bytes in a record), and truncate the remainder of
the division to determine the Block number. Multiplying the remainder of the division by 64
will determine the Register number. For example, if the Log Start Address was 34235, then
the Block and Register numbers containing the first record of Log 2 are:
Block Number = (34235 + 1) / 64 / 2 = 267.46875
Therefore, Block Number 267 contains the starting record.
Record Number = 0.46875 × 64 = 30
Therefore, Register Number 30 contains the first byte of Log 2 data
This location will always be the starting address for Data Log 2 for the given configuration.
Adding or deleting parameters to the configuration will change the Log 2 Starting Address.
The Data Logs will use the maximum amount of memory available, minus a 1 record buffer,
based upon the user configuration. For Example, if the Record Size for a given
configuration was 24 bytes, and there were 40 bytes of memory left in the memory
structure, the Data Logger will not use that last 40 bytes, regardless of the mode of
operation. The Data Logger uses the following formula to determine the total record space
available…
Total Space = (65152 / Record Size) – 1
As in the example, the total space calculated would be 65152 / 24 – 1 = 2713.67. This
equates to 2713 records with 40 bytes of unused memory at the end of Block 511. The
total amount of space used in the structure can also be found in the Log Header in the Log
Total Records field.
When the Data Log is configured for Circulate mode of operation, the memory structure is
the same as for Run to Fill mode. To read the Log data, you must use the Log Starting
Address, Log Record Size, and Log Total Records information from each of the Log
Headers. The Log Starting Address for Log 2 can be determined as shown in the previous
calculation for Run to Fill mode. The total space occupied in the memory structure by
either log is determined by multiplying the Log Total Records by the Log Record Size and
adding this value to the Log Starting Address. It is important to note that the Log Starting
Address is always referenced to the first Register of Block 0, or the first byte of the Data
Log memory structure.
Once you have separated the Data Log data from the Headers, you will then need to
interpret the data into a structured format. Each Record is comprised of user-defined
parameters. These parameters are implemented into the user-defined structure in a
specific order based upon selection into either, or both, Data Log(s). Address 1270h in the
PQM Memory Map is the Holding Register for the first available parameter for use by the
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