CHAPTER 2: MODBUS PROTOCOL
MODBUS PROTOCOL
745 TRANSFORMER PROTECTION SYSTEM – COMMUNICATIONS GUIDE
2–69
Memory map data
formats
F1: Unsigned value (16 bits)
Example: 1234 stored as 1234
F2: Unsigned value, 1 decimal place (16 bits)
Example: 123.4 stored as 1234
F3: Unsigned value, 2 decimal places (16 bits)
Example: 12.34 stored as 1234
F4: Two’s-complement signed value (16 bits)
Example: –1234 stored as –1234
F5: Two’s-complement signed value, 1 decimal place (16 bits)
Example: –123.4 stored as –1234
F6: Two’s-complement signed value, 2 decimal places (16 bits)
Example: –12.34 stored as –1234
F7: Unsigned long value (32 bits)
First block of 16 bits: high-order word of long value
Second block of 16 bits: low-order word of long value
Example: 123456 stored as 123456
F8: Unsigned long value, 1 decimal place (32 bits)
First block of 16 bits: high-order word of long value
Second block of 16 bits: low-order word of long value
Example: 12345.6 stored as 123456
F9: Unsigned long value, 2 decimal places (32 bits)
First block of 16 bits: high-order word of long value
Second block of 16 bits: low-order word of long value
Example: 1234.56 stored as 123456
F10: Two’s-complement signed long value (32 bits)
First block of 16 bits: high-order word of long value
Second block of 16 bits: low-order word of long value
Example: –123456 stored as –123456
F11: Two’s-complement signed long value, 1 decimal place (32 bits)
First block of 16 bits: high-order word of long value
Second block of 16 bits: low-order word of long value
Example: –12345.6 stored as –123456
F12: Two’s-complement signed long value, 2 decimal places (32 bits)
First block of 16 bits: high-order word of long value
Second block of 16 bits: low-order word of long value
Example: –1234.56 stored as –123456
F13: Hardware revision (16-bit enumeration)
Value
Description
Value
Description
1
Hardware revision A
6
Hardware revision F
2
Hardware revision B
7
Hardware revision G
3
Hardware revision C
8
Hardware revision H
4
Hardware revision D
9
Hardware revision I
5
Hardware revision E
10
Hardware revision J