Overview

To allow a consistent sequence of events, a unique time reference is needed to synchronize the local time on each time stamping module of the system.

This time reference can be an NTP server, or GPS receiver modules providing a time reference to an NTP server and directly to the BMX ERT 1604 T modules.

Time Reference Selection

The following table shows the recommended time reference based on the system architecture:

Time Stamping Module in the System

Recommended Time Reference

Description

The system contains only BMX CRA 312 10 time stamping modules

NTP server

An NTP server is connected on the control Ethernet network (if such a network is available on the PLC) or on the Ethernet remote I/O network.

With a unique NTP server available:

  • the PLC synchronizes its time on the NTP server.

  • the BMX CRA 312 10 modules synchronize their clock on the same NTP server.

The system contains at least 1 x BMX ERT 1604 T module

IRIG-B 004/5/6/7 or DCF77 time code from a GPS signal

The GPS provides the time reference to the time sources.

In this case:

  • the PLC synchronizes its time on an NTP server synchronized on a GPS receiver.

  • the BMX CRA 312 10 modules synchronize their clock on the same NTP server as the PLC.

  • the BMX ERT 1604 T modules synchronize their clock on a GPS receiver.

Time Sources for Modules

The following table defines the time sources recommended for each time stamping event source module:

Module

Time Source

BMX ERT 1604 T

GPS time source (IRIG-B 004/5/6/7 or DCF77 time code)

This solution provides the most accurate time source.

Radio receiver time source (DCF77 time code) based on a radio transmitter located in germany near Frankfurt with an action range mainly limited to Europe.

NOTE: For more details on clock sources connection on the BMX ERT 1604 T module, refer to chapter Physical Implementation.

BMX CRA 312 10

NTP server

An NTP server must be available on the Ethernet network accessible from the BMX CRA 312 10 module and set in Control Expert.

NOTE: For more details on NTP server configuration in Control Expert, refer to chapter NTP Configuration in Control Expert.