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Figure 6-18. Alarm Relay Recommended Circuit Configuration
+
-
Load
Fuse
Power Supply
Sig+
Sig-
To
Monitoring
Device
+
-
NC
C
NO
+
-
Load
Fuse
Power Supply
Sig+
Sig-
To
Monitoring
Device
Alarm Relay 2
Normally Open
Configuration
NC
C
NO
Alarm Relay 1
+
-
NC
C
NO
Alarm Relay 2
Normally Closed
Configuration
NC
C
NO
Alarm Relay 1
Note:
The diagrams above are equivalent circuits of what is recommended, the external components shown may be
present internally in the end monitoring device.
Connecting a cable into the alarm relay:
• align the 6-pin phoenix connector with the port contacts
• if not rack mounted, hold the GridTime 3000 in place with one hand
• gently slide the connector into the port until it can’t be pushed any further
Removing a cable from the alarm relay:
• if not rack mounted, hold the GridTime 3000 in place with one hand
• gently slide the connector out of the port
6.7
Installing the GNSS Antenna
This section describes:
• GNSS constellations and signals the GridTime 3000 supports
• how to reliably install an antenna with the GridTime 3000
• how to design your antenna system
• how to connect your antenna cable
The GridTime 3000 features one TNC port which allows for synchronization to time from global navigation satellite
systems (GNSSs). This port is named the ‘antenna port’ and is labeled ‘ANT 1’ on the device’s decal.
A GNSS antenna can be connected to the antenna port through a radio frequency (RF) cable terminated with a TNC
connector. A 50 ohm coaxial cable is recommended.
Unless configured to do otherwise, the device's default settings will always treat GNSS as its highest priority time
source for synchronization even if other time source(s) are also available (NTP, PTP, or IRIG-B).
Four GNSS constellations are supported, and a different upper and lower baseband signal can be received from
each. This is shown in
Baseband Signals of Supported GNSS Constellations
.
Table 6-11. Baseband Signals of Supported GNSS Constellations
GNSS
Lower Baseband Signal
Upper Baseband Signal
GPS/QZSS
L2C (1227.600 MHz)
L1C/A (1575.420 MHz)
Installation
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2022 Microchip Technology Inc.
and its subsidiaries
Manual
DS00004572A-page 51