TCG 01 User Manual
9
th
Edition: February 2007
Page 11 of 49
5.7
P6: Event Recording Inputs or External Sync Input
Two input channels with common return that may be driven by TTL logic
levels. This port is implemented via a 2-pin plug-able connector. Wiring
size is up to 1.0mm
2
and the input is isolated to 2.5kV.
“C” is the common reference (0V), and “+2” and “+1” are TTL inputs 2
and 1 respectively. Input burden is 7mA at 5V.
P6 is used for:
x
Event time tagging or “event recording” on units with this option fitted. For a full
description, see
Appendix C
on page 32.
x
Synchronisation of TCG 01 to an external IRIG-B signal, only in D4 or later
firmware. See Section
8.3.7 Sync to IRIG-B Input
on page 20 for further
information on using this feature.
5.8
P7: Sync Relay
A set of isolated changeover relay output via 3-pin plug-able connector
– capable of switching up to 2A at 230V AC, or 300mA at 150V DC.
Wiring size is to 1.0mm
2
using the supplied mating plug. Isolation is
2.5kV minimum.
This relay is active (“C” and “NO” connected) whenever the TCG 01 has
established stable time sync from the GPS satellites. The active relay output indicates
that all of the other output signals are operating within specification. The connector
accommodates 1mm
2
cabling.
TCG 01 will remain accurate for a time after the loss of satellite sync, and the sync relay
can be configured to remain active (indicating “in sync”) for a period following the loss
of satellite signals. The default period is one minute, but this can be altered up to a
maximum period of 42 minutes and 30 seconds (2550 seconds).
