Allen-Bradley armorstratix 5700, Руководство пользователя, Страница: 152 / 458

152 Rockwell Automation Publication 1783-UM007I-EN-P - December 2017
Chapter 3 Configure Switch Features
GNSS Considerations
Consider these guidelines and limitations when configuring GNSS:
•
GNSS is available as a timing source for PTP only.
•
GNSS is available as a timing source for PTP only when PTP is in
NTP-PTP Clock mode.
•
Syslog messages are sent when the following GNSS events occur:
–
GNSS is in Self-survey mode.
–
GNSS reaches OD mode.
–
GNSS firmware update is in progress, complete, or failed.
•
If the switch is the PTP Grandmaster clock and it loses the antenna
signal, the clock quality can degrade, resulting in a Grandmaster clock
switchover.
•
The GPS antenna alarm does not trigger an external relay alarm.
Configure GNSS
You can configure GNSS as a time source for PTP by using the CLI. For
instructions on how to configure GNSS via the CLI, refer to documentation
available at
http://www.Cisco.com .
By default, GNSS is disabled. The following table lists other default settings.
High-availability
Seamless Redundancy (HSR) HSR is available on Stratix 5400 switches. HSR is defined in International
Standard IEC 62439-3-2016 clause 5.
For instructions on how to configure HSR via the CLI, refer to documentation
available at
http://www.Cisco.com .
Parameter Default
Cable delay—The amount of time to compensate for cable delay in nanoseconds. 0
Antenna power—Antenna power input voltage. 5
Constellation—The satellite constellation that GNSS detects and locks to. GPS
Anti-jam—The number of satellites required for a valid timing fix:
• Enabled—A minimum of two satellites is required for a fix in Over-determined (OD)
Clock mode, and three satellites are required for the first fix in Self-survey mode.
• Disabled—Only one satellite is required for a valid timing fix.
Enabled
IMPORTANT To use HSR, be sure that the switch is using the HSR feature application
profile as described on page 149 .