OMRON ZFX Vision Sensor Engineering Practice

OMRON ZFX Vision Sensor Practice: Full Analysis from Selection to Debugging

In modern industrial automation production lines, visual inspection systems have become the core equipment for quality control and process monitoring. However, facing the dazzling array of visual products on the market, engineers often encounter many challenges during the selection, installation, and debugging stages: how to choose the appropriate camera based on the detection object? How to correctly set up detection areas and tools? How to quickly troubleshoot image instability or misjudgment faults? This article takes the ZFX series, an intelligent visual sensor integrated with an LCD touch screen, as an example, providing a complete engineering practice guide from selection points, hardware connection, parameter configuration, detection tool application, to common problem troubleshooting.

System Overview and Selection Core Elements

The ZFX series visual sensor adopts a split architecture of "controller+camera", and its most prominent feature is that the controller comes with a 3.5-inch TFT color touch screen (resolution 320 × 240), which allows users to complete image settings, define detection areas, and view results in real time without the need to connect an additional computer or monitor. This design significantly reduces the threshold for on-site debugging, especially suitable for equipment integrators and production line maintenance engineers to deploy quickly.

1. Controller selection: Difference between NPN and PNP

The controller is the processing core of the entire system and mainly provides two models:

ZFX-C10: NTP output type

ZFX-C15: PNP output type

The selection should be based on the input polarity of the backend PLC or relay circuit. The power requirement for the controller is 21.6-26.4 VDC (including ripple), with a maximum current consumption of 1.5 A. Therefore, it is recommended to use a stable and reliable 24V DC switching power supply, and pay attention to separate power supply from strong interference sources such as frequency converters and high-power motors. The protection level of the controller is IP20, suitable for installation inside the control cabinet.

Key functional highlights:

Up to 1 camera can be connected (note: data shows 1 camera, but different camera types can be switched)

Supports 32 registered banks, each bank can store 32 testing items

Built in image storage function, saving up to 100 images for traceability

Rich communication interfaces: Ethernet (100BASE-TX/10BASE-T), RS-232C, RS-422, USB 2.0, parallel I/O (12 point input/22 point output)

2. Camera selection: field of view, distance, color, and protection

The ZFX series offers multiple camera models, mainly divided into two categories: "illuminated" and "camera only (with CCTV lens)". When selecting, the following parameters should be considered comprehensively:

(1) Detection range (field of view) and set distance

ZFX-SR10/SC10: Suitable for small parts. The detection range is 5mm × 4.9mm~9mm × 8.9mm (variable), with a set distance of 34-49mm.

ZFX-SR50/SC50: Universal type. The detection range is 10mm × 9.8mm~50mm × 49mm, with a set distance of 38-194mm.

ZFX-SC90: Large field of view. The detection range is 50mm × 49mm~90mm × 89mm, with a set distance of 67~142mm.

ZFX-SC150: Maximum Field of View. The detection range is 90mm × 89mm~150mm × 148mm, with a set distance of 115~227mm.

ZFX-S/SC (camera only): requires optional CCTV lenses (such as 6mm, 8mm, 12mm focal length, etc.), suitable for scenes that require flexible adjustment of working distance or special installation space. At this point, the detection range is completely determined by the lens focal length and object distance, and can be selected based on the optical chart.

Engineering suggestion: When selecting, give priority to models with lighting (SR/SC series), as they have built-in pulse LED lighting and light guide design, which can effectively reduce external environmental light interference. Only when the detection distance exceeds 187mm or specific lenses are required (such as macro, wide-angle), should the "camera only" model be considered.

(2) Color and Resolution

Monochrome: Models with "SR" or "S", suitable for contrast detection, edge positioning, size measurement, etc.

Color: Model with "SC", suitable for color recognition, color difference detection, etc.

All cameras have an effective pixel size of 659 (H) × 494 (V), a pixel size of 7.4 μ m × 7.4 μ m, and a frame rate of up to 96 fps (full frame capture), which can meet the needs of fast moving production lines.

(3) Protection level

Standard type: IP65 (dustproof and water-resistant)

Model with suffix "W" (such as ZFX-SC50W): IP67 (short-term immersion), suitable for humid or dusty environments

3. Cable and accessory selection

The connection cables between the camera and the controller are available in two types: ordinary type and robot bending resistant type, with a length of 3m or 8m. It should be noted that the total cable length between the controller and the camera should not exceed 19m, and a maximum of two extension cables (3m each) can be connected in series. The extension cable model is ZFX-XC3A. In addition, standard models are available for parallel I/O cables, RS-232C cables, monitor cables, etc.

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.

Application: Detect missing parts (small area), foreign object adhesion (abnormal increase in area), and solder diffusion degree.

4. Brightness/Hue Detection

Brightness: measures the average grayscale value within the ROI, used to determine light source aging or workpiece surface reflection.

HUE: detects the hue value of a color camera for color classification (such as distinguishing between red/green/blue labels).

5. Defects detection

Principle: Compare the detected image with the reference image, identify areas of grayscale difference, and output the defect area or quantity.

Application: Surface scratches, dents, printing defects, etc.

6. Sensitive Search

Features: More sensitive to edge and texture changes than ordinary pattern search, suitable for detecting subtle differences (such as electronic component orientation, front and back recognition).

Engineering skills:

When there are batch differences in the detection object, it is recommended to register multiple sample images (multiple templates) or use the "adaptive threshold" function.

For high-speed moving objects (such as 500 or more per minute), the "high-speed" image rate mode should be used, and an external strobe controller (such as Moritex MLEK-C100E1TSX) should be used to freeze motion blur.

Communication and System Integration

1. Ethernet communication

The ZFX controller supports 100BASE-TX/10BASE-T Ethernet and can exchange data with upper computers (PLC, HMI, SCADA) through TCP/IP protocol. Typical applications:

Remote switching of banks

Upload detection images and result logs

View real-time footage through a web browser (customization required)

2. Serial communication (RS-232C/RS-422)

Maximum baud rate 115200 bps

Attention: RS-232C and RS-422 interfaces cannot be used simultaneously

Can be used to connect barcode scanners, printers, or old model PLCs

3. Parallel I/O

Provides 12 point input and 22 point output, with a response time in milliseconds, suitable for direct hard wiring with high-speed PLCs. Enter typical allocation:

TRIG: External trigger signal (rising edge valid)

RESET: Reset alarm or clear output

DI0~DI8: Bank selection (binary code)

Output typical allocation:

OR: Comprehensive judgment (all testing items are OK)

ERROR: System error (such as communication failure, camera malfunction)

RUN: The camera is currently capturing and processing images

ENABLE: Allow triggering (internal state ready)

4. Image data transmission

The images stored inside the controller can be exported to a USB flash drive through the USB interface (MINI-B), which facilitates offline analysis and quality traceability.

Common troubleshooting guide

Even if the selection is correct, various problems are inevitably encountered during on-site debugging. The following is a troubleshooting table based on practical engineering experience summary.

Possible causes and solutions for the fault phenomenon

No image display camera cable connected or broken; Check if the total length of the cable exceeds 19m when the controller is not powered on; measure the 24V power supply; Replace the spare cable

The image is too dark or too bright, and the shutter speed is not appropriate; If the lighting brightness is insufficient, execute 'automatic adjustment' again; Check if the LED lighting is damaged (with lighting model); For "camera only" models, check external lighting or aperture

Frequent misjudgment of workpiece position deviation in detection results without correction; Light changes; Enable position correction tool for background interference; Use polarizing mirrors or install light shields; Adjust the binarization threshold

After triggering, there is no output and the trigger signal has not arrived; Check the TRIG wiring and voltage level when the ENABLE signal is OFF; Confirm that the controller is in the 'waiting to trigger' state

Communication timeout IP address setting error; Confirm that the controller and the upper computer are in the same network segment due to mismatched serial port parameters; Verify baud rate, data bits, and stop bits

The controller displays an "ERROR" red light indicating an internal hardware malfunction; The camera did not recognize the need to restart the power supply; Re plug and unplug the camera cable; Contact technical support

Quick Reference Table for Technical Parameters

For the convenience of on-site engineers to quickly consult, the following are the most critical parameters extracted.

Controller (ZFX-C10/C15)

Power supply: 24 VDC ± 10%, maximum 1.5 A

Protection: IP20

Working temperature: 0~+50 ° C

Storage temperature: -15~+60 ° C

Weight: Approximately 620 grams

Dimensions: Not listed, but comes with stylus, exhaust unit, terminal block adapter

Typical camera (ZFX-SC50)

Detection range: 10mm × 9.8mm~50mm × 49mm

Set distance: 38~194mm

Image sensor: 1/3 inch CCD, color, 659 × 494

Frame rate: 96 fps

Lighting: Red LED pulse lighting (built-in)

Protection: IP65 (SC50), IP67 (SC50W)

Working temperature: 0~+40 ° C (SC50), 0~+50 ° C (SC90/SC150)

Weight: Approximately 270g (including installation bracket and cable)

Cable restrictions

Camera cable up to 19m in length (can be connected in series with two 3m extension cables)

Suggest using original shielded cables