...........continued
Symptom
Probable Cause
Troubleshooting Procedure / Corrective
Action
GridTime 3000 in Holdover
No GNSS position fix
No visible satellites
Check if GNSS Antenna Installtion has a clear
view of the sky.
See
6.7. Installing the GNSS Antenna
for
additional information
Wrong antenna type, cable
length, or power level into
GNSS Antenna port
Check that the antenna installation (including
cables, arrestors, amplifiers and splitters) delivers
sufficient gain into the antenna port, and that the
antenna in use is compatible with the antenna
port's current and voltage specification as per:
12.8. GNSS Receiver Specification
The GNSS receiver requires a gain at the
antenna connector input to be between 17 dB and
50 dB, and the noise figure to be <4dB.
11.4.1
Alarm Conditions and Correction Actions
This section describes the trigger and clearance conditions, and the recommended corrective user action for the
GridTime 3000’s alarms.
Each alarm has unique trigger and clearance conditions based on system observables. Hence, each alarm requires
unique corrective action when triggered.
For guidance on how to monitor the GridTime 3000's alarms, see
Table 11-3. Alarm Trigger and Clearance Conditions Table
Alarm Name
Trigger Condition
Clearance Condition
Recommended
Corrective Action
No Fix
Device lacks reception
of enough usable
1
GNSS
satellites to calculate an
estimate of its position.
Device has reception of
enough usable
1
GNSS
satellites to calculate an
estimate of its position.
If alarm is recurring,
validate antenna
installation using
11.5. Antenna Installation
Troubleshooting
. Ensure
the antenna has a full sky
view.
Satellite Count Low
Number of usable satellites
detected by the device
drops below the minimum
satellites setting.
The minimum satellites
setting can be modified
in the Clock Management
Tool. See
Number of usable satellites
detected by the device
reaches the minimum
satellites setting.
If alarm is recurring,
ensure minimum satellites
setting isn’t too large
(>10).
If it isn’t too large, validate
antenna installation using
11.5. Antenna Installation
Troubleshooting
. Ensure
the antenna has a full sky
view.
Antenna Current High
Current through the
antenna port increases
above 60 mA.
Current through the
antenna port drops below
58 mA.
Electrically test antenna
installation according to
How to Check for a short
in an Antenna Installation
guide.
Maintenance and Troubleshooting
©
2022 Microchip Technology Inc.
and its subsidiaries
Manual
DS00004572A-page 224
