Primary Keyword: SWAS Panel
Secondary Keywords: SWAS Panel Maintenance, Online SWAS Panel, SWAS Panel India
Internal Link Target: /products/swas-panels
CTA: Get a free site-application consultation

Introduction

Modern power plants and industrial steam-generation facilities require continuous visibility of water and steam chemistry. Measuring parameters such as conductivity, pH, silica, sodium and dissolved oxygen is important, but simply displaying the current measurement is not enough.

Plant operators and chemistry teams also need to know:

• What was the chemistry value one hour ago?

• Did the parameter increase gradually or suddenly?

• When did an alarm occur?

• How long did the alarm remain active?

• Was the analyzer under calibration?

• Was sample flow available?

• Did the analyzer experience a fault?

• What was the chemistry condition during a plant startup or shutdown?

This is where SWAS Panel Data Logging and Reporting becomes important.

A properly engineered SWAS Panel can collect measurements from online analyzers, record historical values, store alarm events, monitor analyzer status and provide reports for plant operators, maintenance teams and chemistry departments.

An Online SWAS Panel combined with appropriate data logging can transform individual analyzer readings into useful historical information for plant operation and troubleshooting.

What Is SWAS Panel Data Logging?

SWAS Panel data logging is the process of continuously recording measurements and system-status information generated by a Steam and Water Analysis System.

Depending on the system architecture, logged information may include:

• Analyzer measurements

• Sample temperature

• Sample pressure

• Sample flow

• Analyzer status

• Calibration status

• Alarm status

• Fault conditions

• Reagent status

• Communication status

• Maintenance events

The data may be stored locally in a PLC, HMI, industrial computer, historian or plant-wide data-management system.

Why Data Logging Is Important

A single analyzer reading provides information about the process at one point in time.

Historical data provides a much broader picture.

For example, if silica suddenly increases, operators can examine the trend to determine whether:

• The increase occurred suddenly

• The value gradually increased

• The condition is recurring

• The change coincided with a plant operating event

• The analyzer was undergoing calibration

• Sample flow was unstable

Historical data therefore supports both operation and troubleshooting.

SWAS Panel Real-Time Data

A typical Online SWAS Panel may display real-time measurements on a local HMI.

For example:

ParameterCurrent ValueStatusConductivity0.XX µS/cmNormalCation Conductivity0.XX µS/cmNormalpHX.XXNormalSilicaXX µg/LNormalSodiumXX µg/LNormalDissolved OxygenXX µg/LNormal

The exact parameters and measuring ranges depend on the analyzer configuration.

Real-time values allow operators to see current conditions, while historical logging provides the long-term picture.

Historical Trend Logging

Trend logging is one of the most valuable functions of a SWAS data system.

A trend may show:

Parameter vs Time

For example:

• 1-minute trend

• 5-minute trend

• 15-minute trend

• Hourly trend

• Daily trend

• Weekly trend

• Monthly trend

The appropriate logging interval depends on the parameter, analyzer response time and plant requirements.

Very short logging intervals generate more data but may not always provide additional useful information.

Why Trends Are Important in Cycle Chemistry

Water-steam chemistry problems do not always appear as sudden failures.

Some problems develop gradually.

For example:

Conductivity:
Normal → Slight increase → Continued increase → High alarm

Silica:
Stable → Gradual increase → Warning → High alarm

Sodium:
Normal → Small fluctuations → Increasing trend → Chemistry investigation

A trend can therefore provide an early indication of a developing problem.

Data Logging for Multiple Sample Streams

Large power plants may have several SWAS sample streams.

These may include:

• Condensate

• Feedwater

• Boiler water

• Main steam

• Reheat steam

• Condensate polishing outlet

• Makeup water

Each sample stream may have multiple analyzers.

The data system should clearly identify:

Sample Stream + Parameter + Analyzer + Time

This prevents confusion when reviewing historical data.

SWAS Panel Data Logging Architecture

A typical system may follow this architecture:

Process Sample

↓

SWAS Sample Conditioning System

↓

Online Analyzers

↓

PLC / Data Acquisition System

↓

HMI / Local Display

↓

Plant DCS / SCADA / Historian

↓

Reports and Historical Analysis

This architecture can be customized depending on the plant's automation philosophy.

PLC-Based Data Logging

A PLC can collect signals from:

• Online analyzers

• Flow sensors

• Temperature sensors

• Pressure sensors

• Pumps

• Valves

• Alarm devices

The PLC can then communicate the information to an HMI or plant control system.

Advantages include:

• Industrial reliability

• Centralized signal processing

• Alarm handling

• Interlocking

• Communication capability

• Easy integration with plant automation

The exact PLC platform depends on the project specification.

HMI-Based Data Display

The SWAS Panel HMI can provide operators with a visual overview of the system.

Typical screens may include:

Overview Screen

Displays all sample streams and analyzer status.

Analyzer Screen

Displays individual measurements.

Trend Screen

Shows historical graphs.

Alarm Screen

Shows active and historical alarms.

Maintenance Screen

Shows analyzer and equipment status.

Calibration Screen

Provides calibration-related information.

DCS and SCADA Integration

An Online SWAS Panel can be integrated with the plant DCS or SCADA system.

Depending on the architecture, information may be transferred using:

• 4–20 mA

• Digital signals

• Modbus

• Ethernet communication

• OPC-based systems

• Other industrial protocols

Typical signals include:

• Process measurement

• Alarm

• Analyzer fault

• Calibration status

• Sample-flow status

• Temperature

• Pressure

• Communication status

The final interface should be defined during project engineering.

What Data Should a SWAS Panel Log?

A good data-logging strategy should capture more than analyzer concentration.

1. Process Values

Examples:

• pH

• Conductivity

• Cation conductivity

• Silica

• Sodium

• Dissolved oxygen

• Phosphate

2. Sample Conditions

Examples:

• Temperature

• Pressure

• Flow

3. Analyzer Status

Examples:

• Measurement valid

• Analyzer fault

• Calibration

• Maintenance mode

4. Alarm Events

Examples:

• High

• High-high

• Low

• Low-low

• Sample flow alarm

• High temperature

• Analyzer failure

5. System Events

Examples:

• Power failure

• PLC restart

• Communication failure

• Data-system restart

This additional information is extremely useful when analyzing abnormal events.

Alarm Event Logging

Alarm history is an important component of SWAS reporting.

The system should ideally record:

• Alarm description

• Sample stream

• Parameter

• Alarm time

• Alarm acknowledgement

• Return-to-normal time

• Alarm duration

For example:

Main Steam – Silica – High

Start: 10:42
Acknowledged: 10:44
Normal: 11:18

This provides valuable information for plant investigations.

Alarm Duration

Alarm duration can be particularly useful.

A parameter that exceeds a limit for a few seconds may have a different operational significance from one that remains outside the limit for several hours.

Historical alarm duration can help identify:

• Repeated chemistry disturbances

• Persistent contamination

• Analyzer problems

• Sample-system problems

• Operating-condition changes

Data Quality and Measurement Status

Not every logged measurement should automatically be treated as valid process data.

For example, an analyzer may be:

• Under calibration

• Under maintenance

• In standby

• Experiencing a fault

• Without sample flow

• Without reagent

The data system should therefore record measurement status wherever supported.

This prevents invalid measurements from being interpreted as actual process conditions.

Calibration Data Logging

Calibration information should ideally be retained along with measurement history.

Useful records include:

• Calibration date

• Calibration time

• Analyzer identification

• Calibration standard

• Before-calibration value

• After-calibration value

• Calibration result

• Technician/operator

• Calibration status

This information can help explain changes in analyzer readings.

SWAS Panel Reporting

Data logging becomes much more useful when it can be converted into reports.

Common SWAS reports include:

Daily Chemistry Report

Shows minimum, maximum and average values for selected parameters.

Weekly Report

Provides a broader trend of cycle chemistry.

Monthly Report

Useful for plant chemistry review and maintenance planning.

Alarm Report

Lists chemistry and equipment alarms.

Analyzer Status Report

Shows analyzer availability and faults.

Calibration Report

Provides calibration history.

Maintenance Report

Records maintenance activities and equipment status.

Daily SWAS Chemistry Report

A daily report might include:

ParameterMinimumMaximumAverageAlarm CountConductivity————Cation Conductivity————pH————Silica————Sodium————Dissolved Oxygen————

The exact report structure should be customized according to the plant's chemistry program.

Trend Reports

Trend reports help chemistry teams identify changes over time.

Useful comparisons include:

• Today vs yesterday

• This week vs last week

• Startup vs normal operation

• Before maintenance vs after maintenance

• Before calibration vs after calibration

Trend analysis can help identify slow degradation that may not be obvious from real-time monitoring.

Data Logging During Plant Startup

Startup is often one of the most useful periods for historical analysis.

Chemistry can change significantly during:

• Boiler filling

• Startup

• Steam admission

• Turbine rolling

• Synchronization

• Load increase

Recording these events allows chemistry teams to study the behavior of the cycle.

The data can also help optimize future startup procedures.

Data Logging During Shutdown

Shutdown data can also be useful.

It may show:

• Chemistry changes

• Analyzer behavior

• Sample-flow changes

• Dissolved oxygen changes

• Contamination events

Historical records can help improve shutdown and layup procedures.

Data Logging and Steam Purity

Steam purity monitoring can involve parameters such as:

• Silica

• Sodium

• Conductivity

• Cation conductivity

Historical logging makes it possible to identify whether steam purity is:

• Stable

• Gradually deteriorating

• Improving

• Experiencing repeated excursions

This can help chemistry teams investigate boiler-water carryover, contamination and other potential causes.

Data Logging and Condenser Leakage

Condenser leakage can produce changes in water chemistry.

Historical trends in:

• Conductivity

• Cation conductivity

• Sodium

• pH

may provide valuable information.

A trend analysis can help identify the approximate time at which contamination began.

This is particularly useful when investigating intermittent condenser leakage.

SWAS Panel Data Storage

Data storage requirements depend on:

• Number of analyzers

• Number of sample streams

• Logging interval

• Required retention period

• Reporting requirements

• Plant historian architecture

For large installations, SWAS data may be transferred to a plant historian rather than stored exclusively in the local panel.

Data architecture should be designed during the engineering stage.

Data Backup and Security

SWAS data may be important for operational analysis and maintenance records.

Appropriate systems should consider:

• Data backup

• User access

• Password protection

• System redundancy where required

• Time synchronization

• Network security

• Data recovery

The exact cybersecurity architecture should follow the plant's IT/OT policies.

Time Synchronization

Accurate timestamps are important when comparing:

• SWAS chemistry

• DCS events

• Turbine events

• Boiler events

• Alarm history

• Laboratory results

If different systems have different clocks, it may become difficult to determine which event occurred first.

For this reason, SWAS data systems should use an appropriate plant time-synchronization strategy.

Data Logging and Laboratory Results

Online analyzers and laboratory analysis should complement each other.

Laboratory results can be used to:

• Verify online analyzer performance

• Investigate unexpected trends

• Confirm chemistry excursions

• Support calibration checks

Comparing online and laboratory data can help identify whether an abnormal value is caused by the process or by instrumentation.

SWAS Panel Maintenance and Data Logging

Regular SWAS Panel Maintenance should include verification of the data-logging system.

Maintenance activities may include:

• Checking analyzer communication

• Checking PLC status

• Checking HMI operation

• Verifying data timestamps

• Checking historian communication

• Reviewing missing data

• Testing alarm logging

• Checking storage capacity

• Verifying backups

• Checking DCS communication

A perfectly functioning analyzer is of limited value if its data is not being recorded correctly.

Data Gaps and Missing Information

A good SWAS system should identify periods when data is unavailable.

Possible causes include:

• Analyzer fault

• Communication failure

• Power failure

• PLC fault

• Network interruption

• Maintenance

• Calibration

• Sample-flow failure

Reports should ideally distinguish between:

Zero value

and

No valid data

These are completely different conditions.

Data Validation

Data validation can help identify questionable readings.

Possible validation checks include:

• Analyzer status

• Sample flow

• Temperature

• Pressure

• Rate of change

• Calibration status

For example, if an analyzer reports a value while its sample-flow signal indicates zero flow, the measurement should be treated with caution.

SWAS Panel Data Logging Best Practices

For reliable data management, consider the following:

1. Define the required parameters

Do not log unnecessary information simply because it is available.

2. Select appropriate logging intervals

The interval should reflect the analyzer response and process dynamics.

3. Record measurement status

Distinguish valid measurements from calibration or fault conditions.

4. Record alarm events

Maintain a searchable alarm history.

5. Synchronize system clocks

Ensure consistent timestamps.

6. Provide trend displays

Operators should be able to view historical data easily.

7. Provide report generation

Automated reports reduce manual work.

8. Maintain data backups

Protect important historical information.

9. Integrate with DCS/historian

Avoid isolated data silos where practical.

10. Include data-system checks in maintenance

Data logging should form part of SWAS Panel Maintenance.

SWAS Panel India: Data-Logging Considerations

For a SWAS Panel India project, the data-logging architecture should be discussed with the end user before finalizing the system.

Important questions include:

• Does the plant already have a DCS historian?

• Is a local HMI required?

• How long should data be retained?

• Are daily/monthly reports required?

• Should data be accessible remotely?

• Which communication protocol is preferred?

• Are alarm histories required?

• Is user-level access control required?

• Is data export to CSV/Excel required?

• Is a centralized plant historian available?

These requirements can significantly influence the final SWAS system design.

Online SWAS Panel Data Architecture

A typical architecture may be:

Analyzers

↓

PLC / Data Acquisition

↓

Local HMI

↓

Plant DCS / SCADA

↓

Historian

↓

Reports / Dashboards / Chemistry Analysis

This architecture allows operators, maintenance engineers and chemistry personnel to access the information they need.

Benefits of SWAS Panel Data Logging

A well-designed data-logging system provides:

• Historical chemistry records

• Real-time visibility

• Trend analysis

• Alarm history

• Maintenance records

• Calibration history

• Easier troubleshooting

• Faster identification of chemistry excursions

• Better operator decision-making

• Improved preventive maintenance

• Better communication between operations and chemistry teams

SWAS Data-Logging Checklist

Before commissioning a SWAS data system, verify:

☐ All analyzer parameters identified
☐ Logging intervals defined
☐ Sample streams clearly identified
☐ Analyzer status signals included
☐ Alarm events logged
☐ Calibration events logged
☐ Sample flow logged
☐ Sample temperature logged
☐ Sample pressure logged where required
☐ DCS/SCADA interface tested
☐ Historian interface tested
☐ Time synchronization verified
☐ Data retention defined
☐ Backup strategy defined
☐ User access configured
☐ Trend screens tested
☐ Reports tested
☐ Missing-data indication tested
☐ Data validation strategy defined
☐ Maintenance procedure documented

Frequently Asked Questions

What is SWAS Panel data logging?

It is the continuous recording of analyzer measurements, sample conditions, alarms, equipment status and other information generated by a Steam and Water Analysis System.

Why is historical SWAS data important?

Historical data allows operators and chemistry teams to identify trends, investigate abnormal events, review alarms and compare plant chemistry before and after maintenance or operating changes.

Can an Online SWAS Panel send data to a DCS?

Yes. Depending on the system architecture, SWAS data can be integrated into a DCS, SCADA or plant historian through suitable communication interfaces.

What parameters should be logged?

Typical parameters include pH, conductivity, cation conductivity, silica, sodium and dissolved oxygen, along with sample temperature, flow, pressure and analyzer status where applicable.

Should SWAS alarms be recorded?

Yes. Alarm history is important for understanding the timing, duration and frequency of chemistry excursions and equipment problems.

Should calibration events be stored?

Yes. Calibration history helps explain changes in analyzer readings and provides useful maintenance documentation.

How often should SWAS data be recorded?

The appropriate interval depends on the parameter, analyzer response time, process dynamics and plant requirements. There is no single interval suitable for every SWAS application.

Can SWAS data be exported for analysis?

This depends on the control and data-logging architecture. Many systems can provide historical data through the plant historian, SCADA system or suitable data-export functions.

Does SWAS Panel Maintenance include data logging checks?

It should. Maintenance should verify analyzer communication, PLC/HMI operation, alarm history, data timestamps, historian communication and data availability.

Conclusion

Data logging and reporting transform a SWAS Panel from a simple analytical measurement system into a valuable plant chemistry information platform.

Continuous recording of parameters such as conductivity, cation conductivity, pH, silica, sodium and dissolved oxygen allows operators and chemistry teams to understand not only the current condition of the water-steam cycle but also how it has changed over time.

An effective Online SWAS Panel should record process measurements together with analyzer status, sample conditions, alarms, calibration events and maintenance information. Integration with the plant DCS, SCADA or historian can make this information available throughout the plant.

Reliable data also depends on proper SWAS Panel Maintenance. Communication checks, alarm verification, data-storage checks, calibration records and system backups should form part of the overall maintenance program.

For customers evaluating a SWAS Panel India solution, Prosoft Automation can help design the analyzer, sample-conditioning, data-logging, reporting and automation architecture according to the plant's requirements.

Get a Free Site-Application Consultation

Not sure which SWAS parameters, sample streams, data-logging architecture or reporting functions your plant requires?

Get a free site-application consultation from Prosoft Automation to discuss your application and develop a suitable SWAS configuration.

Explore SWAS Panel Solutions

Download our product catalogue or contact Prosoft Automation for technical assistance with SWAS panels, online water chemistry analyzers, data logging and DCS/SCADA integration.

Prosoft Automation
SWAS | Steam & Water Analysis | Online Water Analyzers | Industrial Instrumentation