Introduction

The BMENUA0100 Ethernet communications module with embedded OPC UA server supports version 4 of the network time protocol (NTP). The NTP service synchronizes the clock in the BMENUA0100 module with the clock of a time server. The synchronized value is used to update the clock in the module.

Both IPv4 and IPv6 protocols are supported.

NOTE:

  • If the NTP server resides in the CPU, the BMENUA0100 module can update its time settings without introducing delay.

  • When a new NTP server is reached or if there is a time offset on an NTP server, it can take up to 5 minutes to update the BMENUA0100. The ERR LED remains ON until the BMENUA0100 time is synchronized with the NTP server.

  • Manually configuring a time change, by inputting a future time, may disconnect the existing OPC UA channels. If the OPC UA client performs an automatic reconnection to the OPC UA server, new channels will be created and the re-connection performed.

Enabling and Disabling the NTP Client and the NTP Server

The BMENUA0100 module includes both an NTP server and an NTP client.

NTP Client:

If either the primary or secondary NTP server IP address is set to a value other than 0.0.0.0, the NTP client is enabled. If both the primary and secondary NTP server IP address settings are empty, or are set to 0.0.0.0 (IPv4) or 0000:0000:0000:0000:0000:0000:0000:0000 (IPv6), the NTP client is disabled.

NOTE: When both Primary NTP Server and Secondary NTP Server IP address settings are set to 0.0.0.0, the BMENUA0100 module cannot operate as either NTP client or NTP server.

NTP Server:

The NTP server is enabled, depending on the cybersecurity operating mode:

  • In Secured mode, the NTP server is enabled if:

    • Either the primary or secondary NTP server IP address setting is set to a non-null value (i.e., set to a value other than 0.0.0.0); and

    • The NTP Server is set to enabled, in the Network Services web page configuration settings.

  • In Standard mode, the NTP server is enabled if either the Primary NTP Server or Secondary NTP Server IP address setting is set to a non-null value (i.e., set to a value other than 0.0.0.0).

NOTE: If the BMENUA0100 is configured as NTP client of a server on the backplane network (Primary NTP Server or Secondary NTP Server ), the BMENUA0100 NTP server will not be enabled in any case, even if there is no NTP server on the backplane network.

When both the NTP server and NTP client are enabled in the BMENUA0100 module, the module NTP client receives time settings over its control port from a remote NTP server. The module NTP server forwards these time settings over its backplane port to NTP clients.

NOTE: The BMENUA0100 module cannot operate as NTP server over its control port.

NTP Polling

The BMENUA0100 module optimally and dynamically manages the NTP polling period with the NTP server. No configuration is necessary.

Power Up

To establish the accurate Ethernet system network time, the system performs these tasks at power up:

  • The BMENUA0100 communications module powers up.

  • The BMENUA0100 communications module obtains the time from the NTP server.

  • The service requires the requests to be sent periodically to obtain and maintain accurate time. Your Polling Period configuration impacts the accuracy of the time.

After an accurate time is received, the service sets the status in the associated time service diagnostic.

The BMENUA0100 communications module does not maintain the time. Upon power up or power cycle, the clock value of the module is 0, which is equivalent to January 1st 1980 00:00:00:00.

Configuring the Service

Configure the network time synchronization service in Control Expert, as follows:

Step

Action

1

In the Project Browser expand the PLC Bus node and open the BMENUA0100 module configuration dialog.

2

Click on the NTP tab.

3

Enter changes in the appropriate fields on the Network Time Service configuration page. (The following table describes the configuration page parameters.)

Configurable Parameters

Configure these time synchronization parameters for each BMENUA0100 communications module in your project:

Parameter

Description

IPv4 NTP server configuration
 

Primary NTP Server (see Note)

Enter a valid IPv4 or IPv6 address for the primary NTPv4 server.

NOTE: Set to the CPU main IP address by default.

Secondary NTP Server (see Note)

Enter a valid IPv4 or IPv6 address for the secondary NTPv4 server.
NOTE:

  • Configure NTP server address that can be reached by the BMENUA0100 module. If the control port is disabled, enter NTP server IP addresses that are in the same subnet as the backplane port.

  • You can configure an IPV4 address for the Primary NTP Server and an IPV6 address for the Secondary NTP Server (and vice versa), if both addresses are in the same domain.

  • For Hot Standby configurations, the NTP serve addresses for NUA(A) and NUA(B) need to be in the same network, for example, the network accessible via the backplane port, or the network accessible via the control port.
NOTE: When operating in secure mode, verify that the NTP service is enabled in the Network Services Activation section of the Settings web page.