Ieee-1344 Extensions; Defining Irig-B Time Codes - GE MultiSync 100 Instruction Manual

THE IRIG-B TIME CODE STANDARD

IEEE-1344 Extensions

Defining IRIG-B Time Codes

Format
1st Digit - Modulation
2nd Digit - Carrier Frequency /
Resolution
3rd Digit - Coded Expressions
10
is normally 5V for on, and 0V for off. Newer IEDs typically use DCLS due to accuracy.
However, the distance to IEDs is limited to around 100m. DCLS typically uses TTL outputs
over shielded, twisted pair cable and BNC connectors.
The original IRIG Standard did not provide year information, or BCDYEAR, in the time code:
only time and day from the start of the year. Lack of year data was a limitation for some
applications, especially in regards to synchrophasors. The IEEE 1344-1995 Standard for
Synchrophasors for Power Systems includes definitions to include year data in the IRIG-B
time code. The IEEE 1344 extensions, as they're commonly known, add calendar year, leap
second, daylight savings time, local time offset, and time quality to the IRIG-B signal.
Individual devices may or may not support the IEEE 1344 extensions.
The IRIG-B Standard was revised in 2004 to include year data. The 200-04 Standard allows
IRIG-B to publish BCDYEAR, as described. The IEEE 1344 Standard has been replaced by
C37.118-2005 IEEE Standard for Synchrophasors for Power Systems, although the term
"IEEE 1344 extensions" is still in common use. The term "C37.118 extensions" may be used
instead.
The IRIG Standard further defines the Time Code Designation to completely describe the
published time code signal.
Table 2–1: IRIG signal identification numbers (3 digits)
A |
B |
D |
E |
G |
H |
0
1
2
Common time code formats are:
• B00x for DC Level Shift
• B12x for amplitude modulated
CHAPTER 2: THEORY OF OPERATION
| | IRIG-A Format
| | IRIG-B Format
| | IRIG-D Format
| | IRIG-E Format
| | IRIG-G Format
| | IRIG-H Format
| | Unmodulated - DC Level Shift, pulse-width coded
| | Amplitude modulated, sine wave carrier
| | Manchester modified
0 | No carrier (DCLS)
1 | 100 Hz / 10 ms resolution
2 | 1 kHz / 1 ms resolution
μs
3 | 10 kHz / 100
μs
4 | 100 kHz / 10
0 BCD , CF, SBS
TOY
1 BCD , CF
TOY
2 BCD
TOY
3 BCD , SBS
TOY
4 BCD , BCD
TOY YEAR
5 BCD , BCD
TOY YEAR
6 BCD , BCD
TOY YEAR
7 BCD , BCD
TOY YEAR
MULTISYNC 100 GPS CLOCK – INSTRUCTION MANUAL
resolution
resolution
, CF, SBS
, CF
, SBS