TEK-NTS03-G+-Manual-v3.-012022
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P10 & P11: Programmable Output (50 OHM BNC connector)
Figure 19 – BNC connector with switch
These two ports provide two high drive, isolated TTL outputs (paired) or two AM IRIG-B
outputs. These ports share a common earth but have separate drivers with the AM IRIG-B
transformer isolated from the rest of the system and the DCLS IRIG-B optically isolated. A
switch located under the connector allows the port to be set up as either an AM or DCLS IRIG-B
port. The switch can be slid to either the DC side to provide DCLS IRIG-B, or to the AM side to
provide AM IRIG-B.
Note
: The switches are delicate and are not designed to be actuated multiple times after
installation. Ideally, they should be actuated once at most during installation to permanently
select the IRIG-B modulation compatible with the installation.
Use either a coaxial cable or a shielded twisted pair (using Tekron BNC to 2 pin adaptor), to feed
a signal from P10/P11 output to any connected IED. When using shielded twisted pair, connect
the shield to ground.
The mark/space amplitude modulation ratio of the AM IRIG-B is 3:1, and peak to peak output
level is 7.2 Vpp (max), 120
Ω
impedance. The output is fully floating and is transformer-isolated
to 3.75 kV.
Most devices with AM IRIG-B time sync inputs have an input impedance of
between 4
kΩ and 20
kΩ, and maximum allowable peak
-to-peak level of 6 V.
The P10/P11 output is designed to drive multiple devices in parallel, with a
terminating resistor (typically 100 - 1
80 Ω) fitted at the far end of the co
-ax. line
feeding all of the attached loads. In this way P10/P11 can drive at least 20, and
typically 30 or more devices without any external amplification. The
terminating resistor is essential to ensure correct voltage levels.
