Function Code 06H Substitution; Memory Map Organization - GE 745 TRANSFORMER MANAGEMENT RELAY Instruction Manual

8.2 MODBUS PROTOCOL
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
DATA STARTING ADDRESS: low order byte
NUMBER OF SETPOINTS: high order byte
NUMBER OF SETPOINTS: low order byte
BYTE COUNT
DATA #1: high order byte
DATA #1: low order byte
CRC: low order byte
CRC: high order byte
Field:
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS: high order byte
DATA STARTING ADDRESS: low order byte
NUMBER OF SETPOINTS: high order byte
NUMBER OF SETPOINTS: low order byte
CRC: low order byte
CRC: high order byte
Data in the 745 that is accessible via computer communications is grouped into several sections of the mem-
ory 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 8–5: MEMORY MAP ORGANIZATION
8
MEMORY MAP SECTION
Product ID
Commands
User Map
Actual Values
Event Recorder
Common Setpoints
Setpoint Group 1/2/3/4
Trace Memory
Playback Memory
8-16
Example (hex):
11
10
11
00
00
01
02
00
C8
6B
07
Example (hex):
11
00
11
00
00
01
06
65
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
query message for slave 11
store multiple setpoints (substituted for code 06H)
data starting at address 1100
1 setpoint values = 2 bytes total
2 bytes of data
data for address 1100 = 00C8
response message from slave 11
store multiple setpoint values
data starting at address 1100
1 setpoint values = 2 bytes total

8.2.18 MEMORY MAP ORGANIZATION

8 COMMUNICATIONS
GE Power Management