2–72
745 TRANSFORMER PROTECTION SYSTEM – COMMUNICATIONS GUIDE
MODBUS PROTOCOL
CHAPTER 2: MODBUS PROTOCOL
F24: Event type and cause (16-bit enumeration)
First block of four bits (0000 ---- ---- ----): type of event, enumerated as follows:
Second block of twelve bits (---- 0000 0000 0000): cause of event, enumerated as follows:
Value
Bit arrangement
Event type
0
0000 –––– –––– ––––
None
1
0001 –––– –––– ––––
Off
2
0010 –––– –––– ––––
On
3
0011 –––– –––– ––––
Pickup
4
0100 –––– –––– ––––
Operate
5
0101 –––– –––– ––––
Dropout
6
0110 –––– –––– ––––
Error
Value
Bit arrangement
Cause of event
0
–––– 0000 0000 0000
No event
1
–––– 0000 0000 0001
Percent differential
2
–––– 0000 0000 0010
Instantaneous differential
3
–––– 0000 0000 0011
Winding 1 phase time overcurrent
4
–––– 0000 0000 0100
Winding 2 phase time overcurrent
5
–––– 0000 0000 0101
Winding 3 phase time overcurrent
6
–––– 0000 0000 0110
Winding 1 phase instantaneous overcurrent 1
7
–––– 0000 0000 0111
Winding 2 phase instantaneous overcurrent 1
8
–––– 0000 0000 1000
Winding 3 phase instantaneous overcurrent 1
9
–––– 0000 0000 1001
Winding 1 phase instantaneous overcurrent 2
10
–––– 0000 0000 1010
Winding 2 phase instantaneous overcurrent 2
11
–––– 0000 0000 1011
Winding 3 phase instantaneous overcurrent 2
12
–––– 0000 0000 1100
Winding 1 neutral time overcurrent
13
–––– 0000 0000 1101
Winding 2 neutral time overcurrent
14
–––– 0000 0000 1110
Winding 3 neutral time overcurrent
15
–––– 0000 0000 1111
Winding 1 neutral instantaneous overcurrent 1
16
–––– 0000 0001 0000
Winding 2 neutral instantaneous overcurrent 1
17
–––– 0000 0001 0001
Winding 3 neutral instantaneous overcurrent 1
18
–––– 0000 0001 0010
Winding 1 neutral instantaneous overcurrent 2
19
–––– 0000 0001 0011
Winding 2 neutral instantaneous overcurrent 2
20
–––– 0000 0001 0100
Winding 3 neutral instantaneous overcurrent 2
21
–––– 0000 0001 0101
Winding 1 ground time overcurrent
22
–––– 0000 0001 0110
Winding 2 ground time overcurrent
23
–––– 0000 0001 0111
Winding 3 ground time overcurrent
24
–––– 0000 0001 1000
Winding 1 ground instantaneous overcurrent 1
25
–––– 0000 0001 1001
Winding 2 ground instantaneous overcurrent 1
26
–––– 0000 0001 1010
Winding 3 ground instantaneous overcurrent 1
27
–––– 0000 0001 1011
Winding 1 ground instantaneous overcurrent 2
28
–––– 0000 0001 1100
Winding 2 ground instantaneous overcurrent 2
29
–––– 0000 0001 1101
Winding 3 ground instantaneous overcurrent 2
30
–––– 0000 0001 1110
Winding 1 restricted ground fault
31
–––– 0000 0001 1111
Winding 2 restricted ground fault
32
–––– 0000 0010 0000
Winding 3 restricted ground fault
33
–––– 0000 0010 0001
Winding 1 restricted ground trend
34
–––– 0000 0010 0010
Winding 2 restricted ground trend