Memory Map Organization - GE TRANSFORMER MANAGEMENT RELAY 745 Instruction Manual

7.3 MODBUS FUNCTIONS
c) FUNCTION CODE 06H SUBSTITUTION
Function code 06h (Store Single Setpoint) is simply a shorter version of function code 10h (Store Multiple Setpoints). Using
function code 10h, such that the Number of Setpoints stored is 1, has the same effect as function code 06h. The message
format and example is shown below.
Request slave device 11 to write the single setpoint value 00C8 at setpoint address 1100.
MASTER QUERY MESSAGE:
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS: high order byte, low order byte
NUMBER OF SETPOINTS: high order byte, low order byte
BYTE COUNT
DATA: high order byte, low order byte
CRC: low order byte, high order byte
SLAVE RESPONSE:
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS: high order byte, low order byte
NUMBER OF SETPOINTS: high order byte, low order byte
CRC: low order byte, high order byte
Data in the 745 that is accessible via computer communications is grouped into several sections of the memory map as
shown in the table below. All memory map locations are two-byte (16-bit) values. The following section lists all memory map
locations. Addresses for all locations are in hexadecimal. Consult the range, step, units, and the data format (listed after the
memory map) to interpret the register values.
Table 7–4: MEMORY MAP ORGANIZATION
MEMORY MAP SECTION
Product ID
Commands
User Map
7
Actual Values
Event Recorder
Common Setpoints
Setpoint Group 1/2/3/4
Trace Memory
Playback Memory
7-12
Courtesy of NationalSwitchgear.com
ADDRESS RANGE DESCRIPTION
0000 to 007F Identification and revision information. Read only.
0080 to 00FF Substitute command locations. Read and write.
0100 to 01FF User Map Values and Addresses. Read and write.
0200 to 07FF Read only.
0800 to 0FFF Read only (except "Event Record Selector Index").
1000 to 1FFF Read and write.
2000 to 3FFF Read and write.
4000 to 47FF Read only (except "Trace Buffer Selector Index" and "Trace Channel Selector
Index")
4800 to 4FFF Read and write.
745 Transformer Management Relay
EXAMPLE (HEX):
11 query message for slave 11
10 store multiple setpoints (substituted for code 06H)
11 00 data starting at address 1100
00 01 1 setpoint values = 2 bytes total
02 2 bytes of data
00 C8 data for address 1100 = 00C8
6B 07 CRC computed by master
EXAMPLE (HEX):
11 response message from slave 11
00 store multiple setpoint values
11 00 data starting at address 1100
00 01 1 setpoint values = 2 bytes total
06 65 CRC computed by slave

7.3.7 MEMORY MAP ORGANIZATION

7 COMMUNICATIONS
GE Multilin