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5.4.2 P4 pin 1 Programmable Output
The user may configure P4 pin 1 to output in with inverted or non inverted polarity:
x
A user configurable number of pulses per second, minute, hour, day with
adjustable pulse-width and offset.
x
IRIG-B and DCF-77 time codes.
Refer to section 6.3 on page 13 for further information:
5.5
Earth stud
An M4 bolt (to chassis) is provided for earthing of cable shields. This
is located under the serial port to the left of the P4 designator.
5.6
P5: BNC output
P5 provides amplitude modulated IRIG-B (B12x) over a BNC connector.
Use either coaxial cable or shielded twisted pair, to feed signal from P5 to
any connected IED. When using shielded twisted pair, connect the shield
to ground.
The mark/space amplitude modulation ratio is 10:3, and peak to peak
output level is 8 volts (max), 100
:
impedance. The output is fully floating,
and is transformer-isolated to a minimum of 2.5kV.
This output is
not
programmable for other types of signal, and the IRIG-B code is
present whenever the unit is powered. The particular IRIG-B data content is as specified
by the configuration program (refer to
IRIG-B Options
on page 22).
Most devices with amplitude-modulated IRIG-B time sync inputs have an input
impedance of between 4k
:
and 20k
:
, and maximum allowable peak- to-peak
level of 6V or so. The P5 output on TCG 01 is designed to drive many of these
devices all in parallel, with a terminating resistor (typically 100-180 ohms) fitted
at the far end of the coax line feeding all of the attached loads. In this way P5
can drive at least 20, and typically 30 or more devices without any external
amplification required. The terminating resistor is essential to ensure good noise
immunity.
