Why Integrate PXI with MES?

In high-volume production and advanced R&D environments, test systems must communicate with Manufacturing Execution Systems (MES) for traceability, quality control, and production intelligence. PXI test systems — known for precision and modularity — are frequently deployed at end-of-line test stations. Connecting them to MES via OPC UA or REST APIs eliminates data silos, reduces manual errors, and enables real-time decision-making.

What Is OPC UA?

OPC UA (Unified Architecture) is a vendor-agnostic protocol widely used in industrial automation. It allows test stations to publish or subscribe to data models securely and efficiently. PXI-based test controllers can act as OPC UA servers or clients to communicate with MES or SCADA systems.

Key benefits:

• ✔ Platform-agnostic and firewall-friendly
• ✔ Supports encryption and user authentication
• ✔ Enables semantic data modeling for devices, test results, and statuses

REST APIs: Simpler, Web-Based Alternative

REST (Representational State Transfer) is widely used in web and enterprise systems. PXI test software (e.g., LabVIEW or TestStand) can act as REST API clients or servers to exchange JSON-formatted test data.

Use cases:

• ✔ Posting pass/fail test results to MES in real time
• ✔ Requesting test parameters from a central database
• ✔ Logging diagnostics or operator comments

For example, after running a measurement with a PXI SMU or scope, your software can send:

POST /api/test-result HTTP/1.1
Content-Type: application/json

{
  "serial": "SN12345678",
  "station": "PXI_RACK_04",
  "test": "continuity_check",
  "result": "PASS",
  "value": "2.5 Ohm"
}
    

PXI Hardware Considerations

Whether you use a stand-alone PXI controller or a modular PXI rack, ensure that the OS environment supports Ethernet and secure communication. Windows and Linux-based PXI controllers can run middleware for OPC UA or host lightweight REST servers in LabVIEW, Python, or C#.

Architecture Overview

Example 1: OPC UA – The PXI controller exposes an OPC UA server that periodically publishes test results and receives test commands. MES subscribes to variables like “DUT_ID” or “Result_Status”.

Example 2: REST API – The PXI system acts as an HTTP client, pushing JSON to the MES web API endpoint after each test cycle.

Tools and Libraries

• LabVIEW OPC UA Toolkit – Native support for both client/server roles
• NI SystemLink – Enterprise data services layer for test assets
• Python Libraries: opcua, requests, aiohttp
• TestStand API Integration – For automated sequences interfacing MES

Security and Authentication

Use token-based auth for REST endpoints and X.509 certificates for OPC UA. Harden your PXI controller OS with firewall rules and regular patches, especially if exposed on production networks.

FAQs

Can I use both OPC UA and REST?

Yes — many hybrid systems use REST for event-based data and OPC UA for real-time monitoring.

Is MES integration possible with CompactDAQ?

Yes, if it’s controlled via a PC or Linux controller that supports the required middleware.

Do I need extra hardware?

Usually no — most PXI controllers have Ethernet/Wi-Fi. Just ensure compatibility with your MES protocol.

Connecting your PXI test rack to an MES platform via OPC UA or REST API enhances traceability, reduces manual errors, and enables smart manufacturing workflows. With the right architecture and tools, your test data becomes part of a seamless factory ecosystem. Explore our Electronic Test & Instrumentation and PXI Platform sections to find integration-ready systems and modules.