GE Grid Solutions
D20/D200 Technical Overview
GE Information
PRPI-019-3.00-10
35
One of the D20ME/ME II serial ports is connected to the demodulated IRIG B port (IRIG,
InterRange Instrumentation Group) of a GPS receiver (or other device), as illustrated in Figure
20. The D20ME/ME II obtains accurate time information from the GPS receiver then regularly
distributes this information to the connected substation devices that require it. For example, the
D20ME/ME II can distribute time information to DNP3 serial outstations capable of DNP3 time
synchronization.
GPS Reciever
GPS Satellites
D20ME Processor
IRIG-B
Distribution of time information to
substation devices and peripherals
Figure 20 D20/D200 Time Synchronization
To support time synchronization, the D20/D200 must be able to support the device’s protocol,
and the device’s protocol must support time synchronization.
A sample of the demodulated IRIG B protocol is shown in Figure 21.
10
1
2
4
8
10 20 40
1
2
4
8
10 20 40
P2
P1
P0
0
20
30
40
50
P3
P4
P5
1
1
2
2
4
4
8
8
10
10
20
20 40 80
100 200
60
P7
P6
50
70
80
90
100
P8
P9
P10
2
0
2
1
2
2
2
3
2
4
2
5
2
6
2
7
2
9
2
10
2
8
2
11
2
12
2
13
2
14
2
15
2
16
Binary '1'
2 msec
(Typical)
Binary '0'
5 msec
(Typical)
Reference
8 msec
Marker
.01 sec
(Typical)
Seconds
Minutes
Hours
Day
Time of Day
Control Functions
Figure 21 Demodulated IRIG B Signal
