Real-Time Label Printing System for Multi-Line Production

Peak Control designed and deployed a real-time production labelling system across 30 roll-forming machines.

The system reads live order data from the PLC, which interfaces with the legacy controller over RS485, and automatically generates per-product labels at the shear — ensuring every product is accurately identified at the point of manufacture.

The Challenge

The site operates a large fleet of legacy roll-forming lines with limited communication capability.

Key constraints included:

• Legacy controllers only accessible via RS485 comms

• Order data residing in the PLC layer, not easily exposed

• Requirement for deterministic, real-time label printing on every cut

• Need to scale across 30 independent machines

• No tolerance for production delays or missed prints

The core challenge was creating a reliable event-driven system that could synchronise label printing with the exact moment of product shear.

Solution Architecture

Peak Control implemented a robust integration layer using Node-RED, bridging PLC data, legacy comms, and label printing.

System Design:

• PLC Integration (via RS485):
  Node-RED reads order and product data from the PLC, which is already interfaced to the legacy controller over RS485

• Shear Event Handling:
  A shear trigger is detected via:

  • Reading a PLC bit (shear complete / cycle flag), or

  • Writing/handshaking trigger bits where required

• Real-Time Data Capture:
  At the moment of shear, Node-RED captures:

  • Product length

  • Profile type

  • Order/job reference

  • Line/machine ID

• Label Generation & Print Execution:
  The system immediately formats and sends the label payload to the printer with zero operator interaction

Key Features

1. Deterministic Shear-Based Triggering

• Labels are printed exactly on cut event

• No polling delays or timing drift

• Optional handshake logic ensures no missed prints

2. RS485 Legacy Integration

• Leverages existing PLC-to-controller comms

• No need to modify legacy machine firmware

• Clean separation between legacy control and modern data layer

3. Scalable Multi-Line Deployment

• Single Node-RED environment handling 30 machines

• Structured flows per line for maintainability

• Easy replication for additional assets

4. Zero Manual Input

• Fully automated label generation

• Operator only applies label to finished product

• Removes transcription errors entirely

5. Production-Safe Architecture

• Non-intrusive to machine control

• Read/trigger-based integration only

• Designed for continuous industrial operation

Results & Impact

• 100% label accuracy tied to actual production output

• Eliminated missed or incorrect labels

• Improved traceability and order tracking

• Reduced operator workload and intervention

• Enabled a data-driven production environment on legacy equipment

Technical Stack

• Integration Layer: Node-RED

• PLC Interface: RS485 communication to legacy controller

• Triggering: PLC shear event bits (read/write handshake)

• Output: Industrial label printers

• Deployment: Industrial PC (on-premise)

Why This Matters

This solution demonstrates how to build a deterministic, event-driven system on top of legacy infrastructure.

By using the PLC as the authoritative data source and synchronising with real machine events, Peak Control achieved:

• High reliability

• Real-time performance

• Seamless integration without full system upgrades

Future Opportunities

This platform opens the door to:

• Live production dashboards (OEE, throughput)

• Order verification and QA logging

• ERP/MES integration

• Remote monitoring and alerting