Bridging Legacy OPC Classic Servers(DA, AE, HDA) to SnapLogic via OPC UA Wrapper

🔍 Problem Statement

In today’s industrial landscape, legacy OPC Classic servers (DA, AE, HDA) remain deeply entrenched across thousands of plants and manufacturing environments. These systems continue to operate reliably, largely because of the longevity of industrial assets—equipment like PLCs, SCADA systems, and DCS platforms are built to last decades. Given the significant initial investment, risk of production downtime, and the complex validation involved in upgrades, organizations are understandably hesitant to replace what isn’t broken.

Many of these systems were implemented before OPC UA existed (OPC Classic emerged in the late 1990s; OPC UA was released in 2008), and even newer devices often retain OPC Classic support to ensure backward compatibility in brownfield environments. While greenfield projects may adopt OPC UA natively, the vast majority of industrial systems are still brownfield—requiring integration with existing infrastructure.

Yet, despite its prevalence, OPC Classic poses growing integration challenges in the modern era:

• ⚠️ Windows dependency via DCOM complicates secure, cross-platform integration—especially across networks and firewalls.

• 🔐 Security vulnerabilities are inherent in a protocol never designed for today’s threat landscape.

• 📉 Scalability limitations make OPC Classic unsuitable for distributed or cloud-based architectures.

• 🔄 Separate specifications (DA, AE, HDA) increase integration complexity compared to the unified OPC UA model.

As industrial operations move toward cloud analytics, real-time monitoring, and predictive automation, the inability to connect legacy OPC Classic systems with modern platforms becomes a critical bottleneck.

🔑 Bridging Strategy: Modernizing OPC Classic Connectivity to Snaplogic Using OPC UA Wrapper

While OPC Classic (DA, AE, HDA) servers continue to serve reliably in industrial operations, their Windows-bound architecture and DCOM dependency make them incompatible with modern, cloud-oriented integration platforms like SnapLogic. To bridge this gap, several OPC UA Wrappers and Gateways are available in the market, such as:

• Unified Automation OPC UA Gateway (used in this use case)

• Matricon OPC UA Wrapper

• Softing OPC UA Wrapper

• Kepware OPC UA Tunneller

• Integration Objects Others from OEM vendors or open-source toolkits

These wrappers act as protocol bridges—exposing OPC Classic data as secure, platform-independent OPC UA endpoints.

In our setup, we leveraged the Unified Automation OPC UA Gateway to transform simulated OPC DA tags from OPC Simulation Server into OPC UA format, which SnapLogic can natively consume.

Step 1: Install and Start the OPC Classic DA Server

1. Download and install the OPC Simulation DA Server.

2. Launch the server and start simulation nodes like:

   • Saw-toothed Waves.Real8

   • Bucket Brigade.Boolean

   • Square Waves.Int2

3. Ensure the server is running and the tags are updating.

Step 2: Install and Configure the OPC UA Gateway

1. Install the Unified Automation OPC UA Gateway or another wrapper on the same machine or a machine that can access the OPC DA server.

2. Launch the Administration tool and set the OPC UA Endpoint details and configure user authentication
   

3. Launch the Configuration tool

   • Add a new OPC COM DA Server connection.

   • Browse for the registered DA server (OPC.Simulation).
   • Start the UA Gateway service.
     

Step 3: Configure SnapLogic – OPC UA Connection

In SnapLogic Designer:

1. Drag any OPC UA Snap into the canvas (e.g., Browse, Read).

2. In the Snap's Account Settings, create a new OPC UA Account:

   • Endpoint URL:
     opc.tcp://<UA-Gateway-IP>:<port

   • Authentication: As per the defined User configuration in  OPC UA Gateway

3. Save and validate the account to ensure the connection is successful.

1. 

🧪 Use Case: Real-Time Anomaly Detection in OPC DA Signal Using SnapLogic

🔍 Overview

In many industrial automation environments, saw-toothed wave patterns are used to simulate cyclic signals. These waveforms linearly ramp up and are expected to reset to zero once they reach their peak. If the reset doesn’t occur within the expected time window, it could indicate:

• A signal stuck in high state

• A delayed reset due to control failure

• Or even corrupted data feed

Our goal is to detect OPC DA Signal: Saw-Toothed Wave Reset Failure Using SnapLogic in Realtime

Workflow:

Snaplogic Pipeline:

🔄 Step 4: OPC UA Subscription

 

• Subscribed to the Saw-Toothed Waves.Real8 node from the OPC DA Simulation Server.

• Publishing Interval: 100 ms

• Sampling Interval: 100 ms

• Execution Duration: -1 (indefinite)

• Subscribed using SnapLogic’s OPC UA Subscribe Snap for continuous real-time data flow.
  
  

• Node Output:
  

Step 5: Data Parsing & Storage

• Parsed each data change message to extract:

  • Node ID

  • Node Value

  • Server Timestamp

• Loaded structured time-series data into Snowflake Data Warehouse for downstream processing

Step 6: Time Series Anomaly Detection

• Implemented a time series anomaly detection query in Snowflake to identify reset failures in OPC DA signal data. The query examines each high-value reading and evaluates whether the expected reset to zero occurs within 5 seconds based on timestamp gaps

• Anomaly logic:

  If a sensor value exceeds Max value(197) and the next value isn't 0 within 5 seconds, an anomaly is flagged.

• This identifies reset failures or signal lockups in the simulated saw-toothed wave patter

SELECT *
FROM (
  SELECT sensor_id, reading_time, reading_value,
         LEAD(reading_value) OVER (...) AS next_value,
         LEAD(reading_time) OVER (...) AS next_time
  FROM sensor_readings
)
WHERE reading_value > 197
  AND next_value != 0
  AND DATEDIFF('second', reading_time, next_time) > 5;

📣 Step 7: Send Real-Time Alerts via Slack

💬 Slack Notification

• Sends formatted alert when anomaly is detected

• Reaches DevOps/SCADA/Automation teams instantly

Example Alert Message:

✅ Conclusion

Legacy industrial systems still form the backbone of many critical operations — and with good reason. Their reliability, longevity, and deep integration into control environments make them difficult to replace. However, integrating these OPC Classic (DA/AE/HDA) systems into modern data platforms is no longer optional in the era of real-time analytics and IIoT.

This post demonstrated how you can:

• Bridge OPC DA servers to SnapLogic using the Unified Automation OPC UA Gateway

• Continuously monitor simulated sensor data (e.g., Saw-Toothed Waves.Real8)

• Detect anomalies in time series data using Snowflake SQL

• Trigger real-time Slack alerts to notify operational teams

✅ The result is a low-cost, non-invasive modernization path that leverages your existing infrastructure while enabling:

• Real-time visibility

• Intelligent anomaly detection

• Scalable cloud-based analytics

• Actionable alerting workflows