Memory Map Information; User Definable Memory Map Area - GE 369 Communications Manual

CGCOMMUNICATIONS GUIDE
6 Memory Map
6.1

Memory Map Information

Note
6.2

User Definable Memory Map Area

369 MOTOR MANAGEMENT RELAY – COMMUNICATIONS GUIDE
• Command 24 (Clear Data Logger Data): This command will clear all the existing data
presently available in the Data Logger feature. Please refer to the 369 Instruction
Manual, chapter 6: Data Logger and 6.6: Data Logger for more information on the Data
Logger feature.
The data stored in the 369 is grouped as setpoints and actual values. Setpoints can be read
and written by a master computer. Actual Values are read-only. All setpoints and actual
values are stored as two-byte values. 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.
Many Modbus communications drivers add 40001d to the actual address of the
register addresses. For example: if address 0h was to be read, 40001d would be the
address required by the Modbus communications driver; if address 320h (800d) was to
be read, 40801d would be the address required by the Modbus communications driver.
The 369 has a powerful feature, called the User Definable Memory Map, which allows a
computer to read up to 125 non-consecutive data registers (setpoints or actual values) by
using one Modbus packet. It is often necessary for a master computer to continuously poll
various values in each of the connected slave relays. If these values are scattered
throughout the memory map, reading them would require numerous transmissions and
would burden the communication link. The User Definable Memory Map can be
programmed to join any memory map address to one in the block of consecutive User Map
locations, so that they can be accessed by reading these consecutive locations.
The User Definable area has two sections:
1. A Register Index area (memory map addresses 0180h-01FCh) that contains
125 Actual Values or Setpoints registers.
2. A Register area (memory map addresses 0100h-017Ch) 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 through-put of data and can eliminate the need for multiple read command
sequences. For example, if the values of Average Phase Current (register address 0306h)
and Hottest Stator RTD Temperature (register address 0320h) are required to be read from
an 369, their addresses may be remapped as follows:
1. Write 0306h to address 0180h (User Definable Register Index 0000) using
function code 06 or 16.
2. Write 0320h to address 0181h (User Definable Register Index 0001) using
function code 06 or 16.
MEMORY MAP
CG43