Unknown Event Response - Hach Event Monitor Trigger System Manual Básico Del Usuario

Reset the baseline
Reset the baseline if the trigger signal was not disabled before maintenance was done. Or if a known
temporary operation caused a significant change in the sensor readings.
1. From the Main Menu, push MAINTENANCE.
2. Enter the user name and password, then push OK.
3. Push Reset>OK.
The monitor calculates the baseline with the current sensor data.

Unknown event response

When an unknown plant event occurs, identify the root cause. There are many possible causes for
plant events, such as normal events or operational changes. Examine the equipment and water
quality to understand the problem and the result.
Examine the sensor operation
When a unknown plant event occurs, first identify if:
• A sensor error occurred that might cause the alarm.
• The sensors operations are normal.
• There are unusual changes in the sensor values. Examine the graphs of the sensor readings
before the alarm.
• The sensors received the correct maintenance.
• A reagent container is empty. This can shift the readings and may trigger an alarm.
• The flow rates changed. Examine the PSI graph to see if there are unusual pressure patterns that
might effect the flows.
Examine the sampling system
If the operation of all the sensors is without problems, examine the sampling system.
Identify if:
• There are blockages or leaks in the sampling system.
• The sampling system is set to off.
• There are air bubbles in the sample line.
• The system was tampered with or damaged by vandalism.
Examine the recorded data
If the sampling system operation is without problems, examine the recorded data.
Identify if:
• There is a loss of communication.
• There are sensor alarms (high, low, frozen).
• There is a low-pressure alarm from the TOC analyzer.
• There are sensor diagnostic messages.
Examine the water conditions
If the problem was not caused by the equipment or communications, the alarm was likely caused by
a true change in the water conditions. Collect data about the operations upstream of the sampling
point to see if there is any rational explanation for the change in water quality. The goal is to identify if
the root cause is a known operations or an unknown cause.
Identify if:
• There was any unusual weather conditions.
• Work was done on or near water mains.
• There was a change in plant operations.
• Different treatment chemicals are being used.
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