Chapter 2 Features and Functions
Indicators
2-12
Getting Started Guide
Indicators
Power Indicator
This indicator lights when the input power is supplied to the Receiver.
The indicator cannot be set or queried via the serial interface.
GPS Lock Indicator
This indicator lights when the Receiver has phase-locked its internal
reference to a 1 PPS derived from GPS satellite signals. The outputs on
the GPS Receiver — 1 PPS, Programmable Pulse Output (59951A)
IRIG-B (59551A), and 10 MHz (58503B) — become usable when first
lock is attained following powerup.
Holdover Indicator
The Receiver lights this indicator when it’s outputs are no longer
phase-locked to the GPS reference. This can happen for several
reasons, the most likely being that the antenna has been disconnected.
It is also possible to force the Receiver into holdover. (Using SatStat
you can do this by selecting
Control->Go to Manual Holdover
on the
Control & Query
form. To recover from manual holdover, select
Control->Recover from Manual Holdover
.)
When in holdover, the outputs are still usable, but the performance
will be degraded from the locked state. The longer the holdover
condition persists, the more degraded the outputs will become. If the
holdover has resulted from loss of GPS satellite tracking and tracking
resumes, the Receiver will automatically recover from holdover and
become locked again.
NOTE
If the Holdover indicator lights before the Receiver has warmed up for
24 hours and successfully locked to GPS for 48 hours, then the Receiver
has not had time to learn the characteristics of the internal reference
oscillator. The specification for Timing Accuracy during holdover may
not be met. This specification applies only after the Receiver has had
sufficient steady-state operation time.
Alarm Indicator
The Receiver lights this indicator to indicate it has detected a condition
that requires attention. If the condition goes away, the indicator stays
illuminated until you aknowledge it by clearing it. See the subsection
“Monitoring Status/Alarm Conditions” in Chapter 5, “Command
Reference,” of the
58503B/59551A Operating and Programming Guide
(58503-90013) for a complete description of the Alarm Byte.
Summary of Contents for 58503B
Page 13: ...1 Getting Started ...
Page 37: ...2 Features and Functions ...
Page 62: ...Chapter 2 Features and Functions In Case of a Problem 2 26 Getting Started Guide ...
Page 63: ...3 Using Option 001 Front Panel Display Keypad 58503B Only ...
Page 75: ...4 58503B Specifications ...
Page 80: ...Chapter 4 58503B Specifications Specifications and Characteristics 4 6 Getting Started Guide ...
Page 81: ...5 59551A Specifications ...
Page 86: ...Chapter 5 59551A Specifications Specifications and Characteristics 5 6 Getting Started Guide ...