Ultra-Slim Expansion I/O Modules for Vision Inspection Devices

Machine vision systems are an integral part of smart manufacturing by capturing and processing image data for object positioning, identification, measurement, and defect detection. Compared to manual inspection, machine vision offers higher speed, consistency, and reliability.

With the development of AI models and big data technology, the accuracy and intelligence of machine vision have been increasing, making it widely used in a variety of industries, including lithium, photovoltaic, electronics, medical, food, and textile.

01 Machine Vision in Lithium Battery Inspection

In lithium battery production lines, machine vision systems are used to automatically detect various defects on power battery cover plates. The cover plates are transported via conveyor belts to different stations, where industrial cameras capture images that are analyzed by the vision system to determine whether the following issues are present:

• Pole column: dents, scratches, contamination, or discoloration

• Pole column film: wrinkles, foreign particles, or bubbles

• Lower plastic part: glue shortage, cracks, or misalignment

• Explosion-proof film: offset, damage, missing film, or scratches

• Explosion-proof valve: reverse installation, dents, bulges, or deformation

• Injection hole: uneven surface, burrs, or scratches

• Welding and non-welding areas: discoloration, pits, or scratches

• Barcode area: dimensional defects or scan failure

02 Decowell Solution for Vision Inspection Systems

In vision inspection systems, Decowell RB Series ultra-slim Expansion I/O modules have earned customer trust with their strong technical performance and reliable quality.

The RB digital output modules are optimized for voltage-type loads, minimizing the need for external pull-up resistors. This significantly simplifies cabinet wiring and ensures system stability and high performance. The RB Series also offers clear cost advantages, faster delivery times, and serves as a reliable alternative to ET200SP, making it a preferred choice among customers.

Typical setup:

• Main PLC: Siemens S7-1500

• Application: Vision inspection for lithium and photovoltaic production lines

• Configuration: 3 RB modules with 366 digital I/O points per device

This project involves a fully automated vision inspection process, using digital I/O signals to control devices such as industrial cameras, relays, and sensors. Among them, the industrial cameras are voltage-driven loads, requiring only a low-power voltage signal to activate. Precise coordination between the part-in-position signal and the camera trigger signal is critical.

The entire system integrates 12 industrial cameras, all of which must complete defect inspection within a cycle time of 1.6 seconds, posing high demands on both signal processing speed and system stability.

03 Decowell Introduction to Digital Output Module Wiring

• Wiring Diagram of Decowell RB-300H and Intermediate Relay:

• Wiring Diagram of Decowell RB-300H and industrial surface array camera:

These two diagrams illustrate how the RB-300H module connects to both current-type and voltage-type loads.

In typical industrial environments, most loads are current-driven, such as relay coils, solenoid valves, and electromagnets. The RB-300H output channels are fully capable of switching these loads on and off reliably.

However, there are also certain voltage-driven loads on site. These devices require only a specific voltage (usually low power) to operate. When the RB-300H output is connected directly to a voltage-driven device, the high internal resistance of the load may lead to a residual voltage at the output terminal even when the module is in the OFF state. This residual voltage could be enough to unintentionally trigger the load.

As a result, in applications involving voltage-driven devices, it is necessary to add a pull-up resistor to the RB-300H output. The recommended resistor value typically ranges from 1KΩ to 10KΩ, depending on the specifications of the load device. Always refer to the device's datasheet for exact requirements.

04 RB Series Ultra-Slim Expansion I/O Modules

The RB input-output module is a compact distributed I/O module developed by Decowell, consisting of an Adapter Module, I/O Modules (DI, DO, AI, AO, Special Function), Power Module, and Terminal Module.

Features:

• Tool-free wiring with large terminal openings

• 45° angled communication ports to reduce stress

• Comprehensive protections: overcurrent, reverse polarity

• Hot-swappable for easy maintenance

• Advanced diagnostics: module-level and channel-level fault detection

• DIN35 rail mounting with spring-release clips for fast installation

Supported communication protocols include PROFINET, EtherCAT, CC-Link, and Modbus TCP, making the RB Series a flexible and scalable choice for industrial automation systems.