Event Storage
Original instructions
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Event Data Format
A dedicated FIFO block provides space for storage and transfer of the event information.
The event data includes the information of edge polarity (rising or falling), event ID, and time quality.
The following table describes the FIFO space distributed for a time stamp data unit:
Reserved
Byte 0
Value
Byte 1
Event ID
Bit 7...0
Byte 2
Bit 15...8
Byte 3
DateAndTime
SecondSinceEpoch
Bit 7...0
Byte 4
Bit 15...8
Byte 5
Bit 23...16
Byte 6
Bit 31...24
Byte 7
FractionOfSecond
Bit 7...0
Byte 8
Bit 15...8
Byte 9
Bit 23...16
Byte 10
TimeQuality
Byte 11
The following table describes the meaning of each data block:
Attribute Name
Attribute Type
Description/Value
Reserved (Byte 0)
BYTE
Reservation for future use.
This byte is set to 0.
Value
BYTE
Value of the variable after change detection:
Bit 0: Falling edge (0), Rising edge (1)
Event ID
WORD
Identification of the variable is automatically assigned by the configuration tool.
NOTE: The identification must be unique for system time stamping.
DateAndTime
TIMESTAMP
Date and time of the variable change detection
The following table describes the format for DataAndTime data block:
Timestamp Type Definition
Attribute Name
Type
Description/Value
SecondSinceEpoch
INT32U
(0...MAX)
FractionOfSecond
INT24U
See the following table for more information on FractionOfSecond
TimeQuality
TIMEQUALITY
–
The time format is defined according to IEC 61850-7-2 Edition 2.
The definitions of the attributes are as follows: SecondSinceEpoch: Number of seconds since midnight (00:00:00) 1970/01/01 (UTC time). FractionOfSecond:
FractionOfSecond
SEC_1970_0...3
UINT32 little endian encoding
FRACT_SEC_0 (LSByte)
B7-B0
FRACT_SEC_1
B15-B8
FRACT_SEC_2 (MSByte)
B23-B16 (B23 = 1 for 1/2 s)
TimeQuality
B7-B0 (B7 = LeapsSecondsKnown)
FRACT_SEC_2 (MSByte)
FRACT_SEC_1 (2nd byte)
FRACT_SEC_0 (LSByte)
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
The following table describes the format for TimeQuality data block:
TimeQuality Definition
Attribute Name
Type
Description/Value
–
PACKED LIST (8 bits)
–
LeapsSecondsKnown
BOOLEAN (B7)
–
ClockFailure
BOOLEAN (B6)
–
ClockNotSynchronized
BOOLEAN (B5)
–
TimeAccuracy
CODED ENUM (B4...B0)
Number of significant bits in the FractionOfSecond
Minimum time interval is 2**-n
For example, Encoding of LeapSecond = 0, ClockFailure = 0, ClockNotSynchronized = 0, TimeAccuracy = 3 bits: TimeQuality = 0x03.
LeapSecondsKnown: This bit is set to FALSE. ClockFailure: Indicates same meaning with the I% (implicit variable) CLOCK_FAILURE. ClockNotSynchronized: Indicates same meaning with the I% (implicit variable) CLOCK_NOT_SYNC. TimeAccuracy: In IEC norm, the TimeAccuracy represents the number of significant bits N in the FractionOfSecond.
Time accuracy is also used to set specific values of TimeQuality as described in the following table:
TimeAccuracy Specific Values
Values
Comments
Invalid
0xx11110
Used in case of buffer full
IO Channel error
0xx11101
Used in case of IO Channel error detection
TSInit
0xx11100
Used in case of synchronization of the values with the client (done by storing a virtual event with 16-ch discrete values inside the buffer)
ClockInSync
0xx11011
Used in case of external clock during synchronization
If several errors are detected, the precedence of TimeAccuracy specific values are:
  1. TimeAccuracy = IOChannelError (highest prioritority)
  2. TimeAccuracy = Invalid or TSInit
  3. TimeAccuracy = ClockInSync
  4. TimeAccuracy = Unspecified
Event ID
Under system solution configuration, the event ID is assigned for each channel by the system to identify which channel the event belongs to. So that, this ID will be packed together with the event data package.
Parameter Type
Symbol
Valid Values
Description
Configuration
Channel x event ID (x = 0...15)
Read-only
Effective range
Channel
Organization
Each group
Under application solution, the event ID will be replaced by the topological address of the channel:
NOTE: Except the event ID for discrete channels, in case of buffer full, this event ID in the event buffer is loaded by SOE uncertain event ID to denote a buffer full or free event. For more details refer to the Behavior Mode section.
Event FIFO Management
The planned space for event storage is limited. You must consider an overflow buffer to handle conditions where the incoming rate of event bursts are greater than the event acquisition rate.
The following configuration and status parameters can be used to manage the overflow issues:
Parameter Type
Symbol
Valid Values
Unit
Description
Configuration
Buffer threshold
Fixed by 70%
%
Effective range:
Module
Organization:
Group 0
Configuration
SOE uncertain event ID
Read-only and assigned by system
–
Effective range
Module
Organization
Group 0
Status Implicit
TIME_STAMP_RECORDS
0...Full value
–
Available in:
Device DDT
IODDT
Debug screen
Status Implicit
BUFF_FULL
0: No full
1: Full
–
Available in:
Device DDT
IODDT
Debug screen
Status Implicit
TS_BUF_FILLED_PCTAGE
0...100%
–
Available in:
Device DDT
IODDT
Debug screen
Status Implicit
UMAS communication error
0: No error
1: Error
–
Available in:
DDT
Device IODDT
Debug screen
Command Implicit
Clear event buffer
A rising edge from 0 to 1 clears the whole buffer
NOTE: Only available for applicative time stamping mode.
–
Available in:
Device DDT
IODDT
Debug screen
TIME_STAMPS_RECORDS: This word contains the number of time stamp records (event number) available in the local buffer. BUFF_FULL: BUFF_FULL bit is set to 1 on buffer full detection. BUFF_FULL bit is cleared after a buffer full threshold is reached, that is, when percentage of events in the buffer is ≤ buffer threshold (70%). Refer to the Behavior Mode for the module behavior for buffer full case.
The event record and detection always stops after the buffer is full. This means that the latest events are lost during the buffer full period.
Buffer threshold: After the buffer is full, the BMXERT module automatically recovers the event record when the buffer occupancy is lower than the buffer threshold. PERCENTAGE_OF_BUFFER_FILLED: Both buffer threshold and TS_BUF_FILLED_PCTAGE use the percentage for indication. The percentages are calculated by group number instead of event number. The event number varies from 1...16 in one group. The number depends on how many channels get the events occurred within the same 0.5 ms sampling window. SOE uncertain event ID: The buffer full event is treated as a special event from a virtual channel, therefore the unique event ID is assigned by the system. After the buffer full event occurs, the buffer full event with this ID is inserted into the event data sequence immediately. For more details refer to the Behavior Mode section.
The SOE uncertain ID is 16 under applicative solution mode. For more details refer to the Event ID topic.
Clear event buffer: A rising edge from 0 to 1 of this command implicit clears the whole event buffer. This parameter is only available for the applicative time stamping mode.
NOTE: The Clear event buffer command must be used to clear the event buffer before the BMXERT1604T/H module is reassigned to new application. Otherwise, the remaining event data of last application can be kept in the buffer.