GE Multilin 869 - Reading Last Trip Target Messages

12-12 8 SERIES PROTECTIVE RELAY PLATFORM – COMMUNICATIONS GUIDE
USING THE MEMORY MAP CHAPTER 12: ABOUT THE MODBUS MEMORY MAP
For example:
Phase A Current value on relay display: 183.594 A
Phase current values read from Phase A Current Modbus registers:
04F5 (31270): 0002
04F6 (31271): CD2A
Combine the two 16 bit values into a 32 bit unsigned value: 183594
Apply the decimal point rule (divide by 1000): 183.594 A
Reading Last Trip Target Messages
Target messages are read through the Modbus Target Message registers.
Table 12-11: Modbus Map entries, Targets
Follow these steps to obtain the Last Trip message:
1. Read address 30273 (0x0110) to obtain the Target Count.
2. Write the value obtained from Target Count register to select the Target Index register
at address, for example: 40230 (0x00E5). This will position the Target Message Index at
newest Target Message.
3. Read the Target Cause register for the newest Target Message to obtain the Target
Message cause.
For example, here are 3 Target Messages, with a Target Count of 3.
In this example, the following values are read from the Target Registers:
In order to interpret the target messages, we need to refer to the appropriate function
codes:
For Target Index #1: Link Error Primary
The value in Target Message Register 0111(hex) is 0x0000.
1st 16 bits High Order Word of Long Value 2nd 16 bits Low Order Word of Long Value
unsigned 32 bits Unsigned Long Value
unsigned 32 bits Unsigned Long Value, 3 Decimal Places
Register: 31270 Register: 312701
0002 CD2A
183594
183.594
Modbus
Address
Hex
Address
Description Min Max Step Units Format
Code
Factory
Default
Size in
Words
8
5
0
8
6
9
8
8
9
8
4
5
30273 0x0110 Target Count 0 256 1 F0 0 1 Y Y Y Y
30766 0x0111 Target Cause 0 0xFFFFFFFF 1 FC134 0 2 Y Y Y Y
Target Index # 3 GND IOC 1 OP
Target Index # 2 GND IOC 1 PKP
Target Index # 1 Link Error Primary
Target Index # 3 Value: 0x00CO, 0xF202
Target Index # 2 Value: 0x00CO, 0xF201
Target Index # 1 Value: 0x0000, 0x0037