Considerations for using an NTP server as the time source

When you set the time synchronization with an NTP server computer, keep the following in mind:
Configuration requirements
  • You can type up to 7 IP addresses or hostnames of NTP server computers, separated by a semicolon.
  • The server name can only contain letters A-Z, a-z, numbers, and the "-" and "." characters.
  • The server name cannot be longer than 99 characters.
  • The server(s) you provide will be validated to check if the configuration is correct.
  • It is critical to have good network connectivity to properly synchronize the module time with the NTP server.
The module behavior
  • Every 15 minutes, and each time that you access the
    Time Management
     page on the module and the
    Time Management
     page on the
    FactoryTalk Historian ME
     Web Diagnostics client, the system checks if:
    • The time synchronization with the NTP server computer is correct.
    • The data packets are transferred from and to the NTP server computer correctly.
  • If data packets are lost, a message appears on the
    Time Management
     page on the Historian website and the
    Time Management
     page on the
    FactoryTalk Historian ME
     Web Diagnostics client, as well as in the
    FactoryTalk Historian ME
     log. The packets may be lost due to the following reasons:
    • Problems with the network connection.
    • Start of the background computer program monitoring the NTP synchronization.
      In such a case, you should check the log and/or the
      Time Management
       page on the
      FactoryTalk Historian ME
       Web Diagnostics client for any error messages which may have occurred before this situation.
  • If there occurs a clock drift of 500 ppm or the NTP server cannot be reached to synchronize the time, an error message appears:
    • On the
      Time Management
       page on the Historian website.
    • On the
      Time Management
       page on the
      FactoryTalk Historian ME
       Web Diagnostics client.
    • In the
      FactoryTalk Historian ME
       log.
  • If you used a
    FactoryTalk Historian SE
     server for time synchronization, and you upgrade your system to the current
    FactoryTalk Historian ME
     version, your setting will be visible under the
    NTP Server
     option, and the time will be synchronized with the server automatically, provided that it had been configured correctly.
  • If you restore a configuration that used a
    FactoryTalk Historian SE
     server for time synchronization, your setting will be visible under the
    NTP Server
     option, and the time will be synchronized with the server automatically, provided that it had been configured correctly.
The NTP server-related information
  • NTP server computers are typically maintained by a corporate IT department and are often used as the Windows Active Directory server computer on the network.
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