- Power Measurement Modem User's Guide

ION 7500 / ION 7600 User’s Guide Diagnostics and Event Logging
Time Synchronization & Timekeeping Technical Note Page 355
Diagnostics and Event Logging
The meter’s Diagnostics module includes output registers that provide time
synchronization diagnostics. Events are logged by the meter’s Clock module,
Communications modules, and Diagnostics module in response to time
synchronization events.
Diagnostics Module Output Registers
 Time Sync Source
This register is
ON if the internal clock synchronizes with the line frequency or
GPS, and it is
OFF if the internal clock synchronizes with its own internal crystal.
 GPS Receiver Status
This register is
ON if the GPS receiver is locked onto a time source and OFF if the
lock is lost. This information is received directly from the GPS receiver; the
register is
NOT AVAILABLE if the GPS time synchronization is not used.
 Time Sync Count
This register indicates how many time synchronization signals have been
received. The value increases with each signal received.
 Time Since Last Time Sync
This register displays the amount of time, in seconds, since the last time
synchronization signal was received.
 Time Sync Diag (time sync diagnostics)
This register displays the difference, in microseconds, between the timestamp
in a synchronization signal and the time in the device’s clock when the signal is
received. The displayed value is a sliding window average over the last five
time synchronization signals received.
 Time Sync Status
This register is
ON if a time synchronization signal is acquired, and OFF if the
signal has been lost. The Diagnostics module calculates the average interval for
the last five signals received, considering the signal lost if no signals are
received in two times the average interval.
Event Logging
The following events appear in the Event Log:
 Time sync acquired — generated when the first time sync signal is received
(Diagnostics module’s Time Sync Status register goes
ON).
 Time sync lost event — generated if no time sync signals are received in two
times the average interval of the last five signals (Diagnostics module’s Time
Sync Status register goes
OFF).
 GPS locked — generated when the GPS receiver locks onto a time source
(Diagnostics module’s GPS Status register goes
ON).