Overview

Time stamped variable value consistency between the process and the SCADA is a key point in system time stamping solution. To manage that consistency, in addition to the time stamped transitions flow (regular events flow), the system time stamping solution manages the report of process values to the SCADA system even when the system is facing operating modes that differ from the normal operating conditions.

Operating modes that differ from the normal operating conditions:

  • Reset and restart of the time stamping source module.

  • Too many events in a source of events (buffer full).

  • Reset and restart of the SCADA server.

Reset and Restart

Immediately after a restart of the time stamping source module or the relevant SCADA servers, the process values are provided to the SCADA client in order to have value consistency.

The process value flow is then provided in addition to the event data flow with respect to time stamping order.

The SCADA server is informed of process value transmission with a specific value: QualityHighByte = TSInit.

Source of Events Module Internal Buffer Full

A time stamping source module internal buffer should not be full in normal operating conditions, but it can become full in case of disconnection between the module and the SCADA servers for example.

The system time stamping solution can generate non-accurate process values transitions between the buffer full detection and the time when a percentage of the buffer is free again. The SCADA server is informed of non-accurate process values transitions with a specific value: QualityHighByte = Invalid.

The buffer threshold (the value cannot be modified) below which the time stamping module can time stamp events is:

  • 50% of buffer full for the BME P58 ••••

  • 70% of buffer full for the BMX ERT 1604 T

  • 80% of buffer full for the BM• CRA 312 10

SOE Uncertain Event

In case of reset and restart or buffer full, the event detection is frozen and some events may be lost. Time stamped SOE uncertain events are sent to inform the SCADA server of the beginning and end of an uncertain sequence of events. SOE_UNCERTAIN values:

  • SOE_UNCERTAIN = 1: Events might be lost in the following sequence of events.

  • SOE_UNCERTAIN = 0: No event lost in the following sequence of events.