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ABB Distribution Protection Unit 1500R/2000R
has internal time markers, which insure time-stamping accuracy to the millisecond. An eight-millisecond frame reference
marker appears during the first ten milliseconds of each frame. Another eight-millisecond position identifier appears
during the ninetieth millisecond of each one-hundred millisecond period mark. The 30 bit Binary Coded Decimal time
data occurs in the first one hundred millisecond of each 1-second frame. Optional control functions are sometimes
encoded in the data stream. These functions control deletion commands and allow different data groupings within the
synchronization strings. Decoding an IRIG B pulse is quite a complex undertaking. A typical 1-second time frame is
illustrated in Figure 2. It is interesting to note that the year is not included within the IRIG B frame. If the Control
Function frame (CF) or Straight Binary Time of Day frame (SBT) is not used, the bits defined within those fields are to
be set as a string of zeroes and sent to the IED IRIG B receiver.
IRIG B is defined for code format sets identified by a three digit format number. Permissible format numbers for the
IRIG B subsets are:
IRIG B XYZ Where:
The first field "X" identifies the encoding type of the IRIG B signal. DPU/TPU/GPU products support Pulse Width
Code (X= 0), whereas, REL 3XX products having an IRIG B PONI Card support Pulse Width Code and Sine Wave
Amplitude Modulated, and REL5XX products support Sine Wave Amplitude Modulated IRIG. Manchester Modulated
code was added in IRIG Standard 200-98 Dated May 1998. It is not supported in the ABB protective relay products
which are IRIG B capable.
The second field "Y" determines if a carrier is included within IRIG B Data format.
The third field "Z" determines if a combination of the BCD time/Control Function/Straight Binary Time is included
within the IRIG B time frame. The inclusion or exclusion of any of the fields may cause errors in receivers not designed
for the field's inclusion/exclusion.
The following combinations may seem daunting, but only a subset of the listed formats are actually defined within the
specification.
IF X =
0
= Pulse Width Code
1
= Sine Wave Amplitude Modulated
2
= Manchester Modulated Code
IF Y =
0
= No Carrier
2
=1Khz , 1mS
3
=10Khz, 0.1 mS
4
=100 Khz, 10 mS
5
=1Mhz, 1mS
13-2
1 Second Frame in 10 mS increments
0
10
20
30
Seconds Minutes
Hours
Days
Marker Pulses every 10 mS for an 8 mS duration
Figure 2. IRIG B Frame Construction
website:www.abb.com/papd
40
50
60
Control
Functions
Straight
Binary
70
80
90
Time of
Day
Applications Notes
9/99
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