GE Power Quality Meter Series, Инструкция по эксплуатации

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7-14 PQM Power Quality Meter GE Power Management
7.3 MODBUS MEMORY MAP 7 MODBUS COMMUNICATIONS
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7.3 MODBUS MEMORY MAP 7.3.1 MEMORY MAP INFORMATION
The data stored in the PQM is grouped as Setpoints and Actual Values. Setpoints can be read and written by a
master computer. Actual Values can be read only. All Setpoints and Actual Values are stored as two byte val-
ues. That is, each register address is the address of a two byte value. Addresses are listed in hexadecimal.
Data values (Setpoint ranges, increments, factory values) are in decimal.
7.3.2 USER-DEFINABLE MEMORY MAP
The PQM contains a User Definable area in the memory map. This area allows remapping of the addresses of
all Actual Values and Setpoints registers. The User Definable area has two sections:
1. A Register Index area (memory map addresses 0180H-01F7H) that contains 120 Actual Values or Set-
points register addresses.
2. A Register area (memory map addresses 0100H-017FH) that contains the data at the addresses in the
Register Index.
Register data that is separated in the rest of the memory map may be remapped to adjacent register
addresses in the User Definable Registers area. This is accomplished by writing to register addresses in the
User Definable Register Index area. This allows for improved throughput of data and can eliminate the need for
multiple read command sequences.
For example, if the values of Phase A Current (register address 0220H) and Phase A Power Factor (register
address 02DDH) are required to be read from a PQM, their addresses may be remapped as follows:
1. Write 0220H to address 0180H (User Definable Register Index 0000) using function code 06 or 16.
2. Write 02DDH to address 0181H (User Definable Register Index 0001) using function code 06 or 16.
A read (function code 03 or 04) of registers 0100H (User Definable Register 0000) and 0101H (User Definable
Register 0001) will return the Phase A Current and Phase A Power Factor.