Sel 551 - Page 263

G.27
Date Code 20110408 Instruction Manual SEL-551 Relay
Modbus RTU Communications Protocol
Modbus RTU Communications Protocol
NOTE 1: Reserved addresses return 8000h.
NOTE 2: Registers (RW) are read-write registers. Registers (W) are write-
only registers. All other registers are read-only.
NOTE 3: Event Types
0101 Event neg.-seq.
current IQ
Amps 0 65535 1
0102–010F Reserved
Maximum Current Limit
0110 Phase current
d
Amps –32767 32767 1 1
0111 Phase current
e
Exponent –4 4 1 1
0112 Neutral current
d
Amps –32767 32767 1 1
0113 Neutral current
e
Exponent –4 4 1 1
0114–011F Reserved
Communication Counter
0120 Number of messages
received
b
– 0 65535 1 1
0121 Number of messages
sent to other devices
b
– 0 65535 1 1
0122 Invalid address
b
– 0 65535 1 1
0123 Bad CRC
b
– 0 65535 1 1
0124 UART error
b
– 0 65535 1 1
0125 Illegal function
code/Op code
b
– 0 65535 1 1
0126 Illegal register
b
– 0 65535 1 1
0127 Illegal write
b
– 0 65535 1 1
0128 Bad packet format
b
– 0 65535 1 1
0129 Bad packet length
b
– 0 65535 1 1
012A Reserved
Reserved
Reserved
1FFB Device tag #
b
15043 – – – –
1FFC Feature set ID
b
0
1FFD Reserved
Reserved
FFFF Reserved
a
Two 8-bit ASCII characters per register.
b
16-bit unsigned value.
c
16-bit signed value.
d
Two 16-bit registers needed to accomplish the Signed Integer Dynamic Fixed Point data
format. Final value read = (R1 • 10
R2
).
e
R1 is the content of register 0110h (0112h). R2, which is stored in 0111h (0113h), determines the
decimal point position for the final value.
Table G.18 Modbus Map (Sheet 15 of 15)
Address
(Hex)
Field Units
Range
Scale
Factor
Low High Step