5.2.1
Standard Inputs and Outputs
Timing signals to external equipment originate from the J2 connector
block terminals. Terminal block J2 provides one unmodulated IRIG-
B, one modulated IRIG-B, two programmable pulse outputs (A & B),
ground and a set of Form-C relay contacts.
5.2.2
Digital Drivers
The Model 1095A/C has three high-drive digital outputs capable of
supplying 250 mA at greater than 4 Vdc. These outputs are defined
as one (1) unmodulated IRIG-B, and two (2) programmable pulse, one
(Channel B) which may be configured as a second unmodulated IRIG-
B. Each output may be fanned out to a number of receiving devices,
depending on the overall load of the receiving devices. To determine the
maximum number of devices that the digital drivers can support, you will
need to sum the individual load currents for each device connected to
the Model 1095A/C. Greater loads tend to improve the voltage stability.
5.2.3
Analog Drivers
The Model 1095A/C has one analog driver available exclusively for
modulated IRIG-B signals
.
The analog driver supplies a 4.5 Volt
peak-to-peak signal through a 19.6-ohm source resistor to connected
equipment. As the load current increases, the voltage drop increases
across the clock source resistor reducing drive voltage. Make sure to
match the modulated output to within the required voltage range of the
receiving device. Table 5.1 shows how the actual drive voltage varies
with increasing load current. For IED’s with a restricted input range,
match the available drive voltage to the IED through a dropping resistor
of adequate power rating.
Drive Current, mA
Actual Drive Voltage, Vpp
0
4.5 (no load)
1
4.48
10
4.3
100
2.54
Table 5.1: Drive Current vs. Voltage
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