OMRON ZFX Vision Sensor Engineering Practice

Hardware installation and electrical connection

1. Key points of mechanical installation

The installation of the camera must be firm and avoid vibration. According to the specifications, the camera needs to withstand a vibration test of 10~150Hz and a single amplitude of 0.35mm, but it is recommended to use a shock absorber bracket in practical applications.

The camera with illumination (SR/SC series) comes pre installed with a lens and illumination at the factory, without the need for user focusing. Simply adjust the installation distance to change the field of view.

For the "camera only" model (ZFX-S/S C), it is necessary to choose CCTV lenses and extension tubes by yourself, and pay attention to cleaning the image sensor during installation to avoid dust pollution.

2. Electrical wiring specifications

Power supply: The controller is powered by 24VDC ± 10% (21.6-26.4V). It is recommended to use PELV (Protection Extra Low Voltage) power supply and install a magnetic ring (with two ferrite cores attached) at the input of the controller power supply to suppress high-frequency interference.

I/O interface: Parallel inputs include RESET, DSA, DI0~DI8, TRIG (external trigger); The output includes 22 points, including OR (overall judgment), ERROR (error), RUN (running), ENABLE (trigger allowed), GATE, STGOUTO, and DO0-DO15. Pay attention to the differences between NPN and PNP models when wiring.

Grounding: The controller casing must be grounded. The camera is grounded with the controller through a cable shielding layer to avoid forming a ground loop.

Communication line: Ethernet and serial port lines should be routed separately from the power line, with a distance of at least 200mm.

3. Trigger mode selection

The ZFX controller supports multiple triggering methods: internal triggering (continuous detection), external triggering (via TRIG signal), and manual triggering through the touch screen. For high-speed assembly lines, it is recommended to use external triggers and synchronize with the production line encoder to obtain stable detection results.

Parameter Setting and Calibration: Touchscreen Practice

The most prominent convenience of the ZFX series lies in its built-in LCD touch screen. The following are the operations that engineers used to need to connect laptops on site to complete, now they only need to touch on the controller panel.

1. Initial setup process

Language selection: Supports switching between Japanese and English.

Camera registration: After connecting the camera, the system automatically recognizes the model. If using the "camera only" model, you need to manually enter the lens focal length and installation distance.

Image automatic adjustment: Click "Auto Adjustment", and the system will automatically adjust the shutter speed (range 1/170s~1/20000s), lighting brightness, and gain to achieve the best image contrast. This feature is particularly beginner friendly.

Detection area setting: Select the region of interest (ROI) on the touch screen, which can be placed in any position and size.

Add detection tool: Select the required tool from the tool library (see next section for details) and set the qualification threshold.

2. Banking and Project Management

Each bank is equivalent to an independent testing formula, which can store up to 32 banks. For example, Bank1 is used to detect part A, and Bank2 is used to detect part B.

Each bank can add up to 32 testing items in order. When all items are judged OK, the total output (OR) signal is ON.

Bank switching can be completed through external DI signals or Ethernet commands.

3. Position correction function

Due to the possible displacement of the workpiece on the conveyor belt, ZFX provides powerful position correction function:

Single model search: Use a pattern as a reference to correct X, Y, and angle offsets.

Dual model search: using two feature points to correct for more complex rotations and scaling.

Measurement after position correction: All subsequent detection tools (such as area, width, edge) will be based on the corrected coordinate system, greatly improving detection stability.

Detailed explanation and application scenarios of detection tools

The ZFX series comes with approximately 20 built-in inspection tools, covering areas such as shape, size, edge, brightness, color, and defect detection. The following are the most commonly used tools and their typical applications.

1. Pattern Search

Principle: Find the area in the image that best matches the registration template, and output the similarity (0-100%) and position coordinates.

Application: Positioning of workpieces, direction recognition, and quality inspection of character printing.

Parameters: Matching threshold can be set (such as 80%), supporting rotation range (± 180 °) and scaling range (50%~200%).

2. Edge Inspection

Width: measures the distance between two edges, suitable for workpiece outer diameter, gap, and weld width.

Position: detects changes in the position of edges, used for alignment or offset monitoring.

Count: Count the number of edges, such as gear teeth and cable cores.

3. Area

Principle: After binarization, count the number of pixels in bright or dark areas.