OMRON ZX laser sensor maintenance

OMRON ZX laser sensor maintenance

In the field of precision displacement measurement and positioning detection, the OMRON ZX series intelligent laser sensors have become a commonly used choice in industries such as electronic manufacturing, semiconductor equipment, and mechanical positioning due to their high resolution, rich beam shapes, and flexible computing expansion capabilities. However, with the aging of equipment, changes in on-site environment, or model updates, engineers often face practical problems such as selection confusion, decreased accuracy, laser safety compliance, communication configuration, and troubleshooting. This article is based on the ZX series technical manual, providing a complete set of technical references from six dimensions: model identification, installation and wiring, parameter optimization, laser safety specifications, common fault handling, and maintenance replacement strategies.

Key points for model identification and selection

The ZX series consists of two parts: a sensor head and an amplifier unit, which are connected by dedicated cables. All sensor heads and amplifier units are compatible and interchangeable.

1.1 Classification of Sensor Heads

Type Beam Shape Model Example Measurement Range Resolution * Typical Applications

Diffuse Reflection Point Light ZX-LD40 40 ± 10mm 2 μ m General Object Distance

Diffuse reflection point light ZX-LD100 100 ± 40mm 16 μ m medium distance

Diffuse Reflection Point Light ZX-LD300 300 ± 200mm 300 μ m Long Distance

Diffuse reflection ray light ZX-LD40L 40 ± 10mm 2 μ m rough surface

Diffuse reflection ray light ZX-LD100L 100 ± 40mm 16 μ m step surface

Diffuse reflection ray light ZX-LD300L 300 ± 200mm 300 μ m long distance

Positive Reflection Point Light ZX-LD30V 30 ± 2mm 0.25 μ m Mirror Object

Positive and negative ray light ZX-LD30VL 30 ± 2mm 0.25 μ m mirror rough surface

Shooting type - ZX-LT001 0~2000mm 4 μ m * edge detection

Shooting type - ZX-LT005 0~500mm 4 μ m * small object detection

Shooting type - ZX-LT010 0~500mm 4 μ m * medium width

Shooting type - ZX-LT030 0~500mm 4 μ m * 30mm width

*Resolution: The diffuse reflection type is the value at an average frequency of 4096; The value of the average number of reflections is 64.

Selection key:

Measurement object material: Highly reflective or mirror like objects (such as wafers, polished metals) must use the anti reflective type (ZX-LD30V/VL), otherwise saturation or false signals will be generated. Ordinary diffuse reflection type is suitable for matte surfaces.

Surface texture: For materials with rough surfaces and concave convex patterns, it is recommended to use a line beam (suffix L), which can evenly eliminate local undulations and improve stability. Spot light is easily affected by a single convex point.

Measurement distance: Short distance high-precision (within 40mm), choose LD40/LD40L (2 μ m resolution); Select LD100/LD100L for medium distance (100mm); Select LD300/LD300L for long-distance (300mm) (but with lower accuracy).

Shooting type: suitable for edge positioning and detection of small objects. Note that the measurement width (1mm, 5mm, 10mm, 30mm) should be greater than the size of the object being measured.

1.2 Selection of amplifier units

The amplifier unit is divided into NPN output (ZX-LDA11-N) and PNP output (ZX-LDA41-N), both of which have the same function. Key parameters:

Measurement cycle: 150 μ s (fixed), response time can be adjusted by averaging (1~4096) times.

Response time calculation: First output=Measurement cycle x (average times+1); Subsequent output=measurement cycle (when the average number of times is ≥ 2).

Linear output: switchable current (4-20mA) or voltage (± 4V, ± 5V, 1-5V), selected through the bottom switch.

Judgment output: HIGH-PASS/LOW three channel NPN/PNP open collector electrode output, 30V DC, 50mA.

Auxiliary inputs: laser OFF input, zero reset input, timing input, reset input.

Function: Includes sampling hold, peak hold, valley hold, peak peak hold, delay hold, deviation output, two-point teaching, position teaching, automatic teaching, calculation function (A-B, A+B, ZX-CAL2 required), mutual interference suppression, etc.

Selection tip: When multiple sensor data calculations (such as thickness difference and sum) are required, the ZX-CAL2 computing unit must be purchased. When connecting to a computer to record data or configure parameters, it is necessary to purchase the ZX-SF11 communication interface unit and ZX-SW11EV3 logging software.

Installation and wiring specifications

2.1 Mechanical Installation

Sensor head protection level: diffuse reflection type IP40, forward reflection type IP60, opposite reflection type IP60. Avoid installation in areas with severe oil mist, water splashes, and dust.

Vibration tolerance: 10-150Hz, 0.7mm dual amplitude, 80 minutes in all directions. Impact resistance: 300m/s ², 3 times in each of the 6 directions.

Environmental temperature: 0~50 ° C, no freezing or condensation. Storage temperature: -15~60 ° C.

2.2 Electrical wiring

Amplifier unit terminal (taking ZX-LDA11-N as an example):

Brown:+24V DC

Blue: 0V

Black: Linear output (current/voltage)

Shielded wire: Linear output ground (needs to be separated from 0V to avoid noise)

White: Judgment output 1 (HIGH)

Gray: Judgment output 2 (PASS)

Pink: Judgment output 3 (LOW)

Green: laser OFF input/zero reset, etc

Yellow: timed input/reset, etc

Important wiring rules:

Use a dedicated regulated power supply, especially when high resolution is required, to avoid sharing power with large interfering devices such as frequency converters and motors.

The linear output ground (shielded wire) must be grounded separately from 0V and cannot be directly short circuited, otherwise it will introduce common mode noise.

The total cable length (sensor head+extension cable) shall not exceed 10m. The extension cable must use ZX-XC □ A series (1m, 4m, 8m, 9m) and must be shielded twisted pair.

Do not lay the power cord (24V/0V) in the same cable tray as the high-voltage or power cord to prevent electromagnetic interference.

2.3 Sensor head cable connection

The sensor head comes standard with a 0.5m cable, which is connected to the amplifier unit through a connector. When extending, use ZX-XC □ A. Note: The reflective sensor (ZX-LT * * *) cable cannot be mixed with the reflective extension cable.

Parameter Setting and Optimization

3.1 Average frequency and response speed

The average count can be set to 1, 2, 4,..., 4096. The higher the average frequency, the better the resolution, but the longer the response time. Calculation formula:

First output delay=150 μ s × (average times+1)

Subsequent output cycle=150 μ s (when the average frequency is ≥ 2)

For example, the average number of times is 4096, with an initial output of approximately 614.6ms and subsequent outputs every 150 μ s. If quick response (<1ms) is required, the average number of times should be ≤ 8.

3.2 Teaching Methods

Two point teaching: Place the target object in two extreme positions, record the teaching values separately, and automatically set the threshold.

Location demonstration: Place the target object at the detection position and directly set the threshold.

Automatic teaching: Move the object being tested, and the sensor automatically captures the maximum and minimum values and sets a threshold.

Direct threshold setting: manually input numerical values.

3.3 Maintain Functionality

Sample hold: Lock the current measurement value at the rising edge of the timed input.

Peak/valley value maintenance: Continuously track the maximum or minimum value.

Peak to peak retention: tracks the difference between the maximum and minimum values.

Delay hold: Hold after delay.

Self peak/self valley value: automatically updated during each measurement cycle.

3.4 Calculation function (requires ZX-CAL2)

After connecting two amplifiers through ZX-CAL2, they can perform A-B (difference) or A+B (sum) calculations and output the results as new measurement values. For example, when measuring thickness, the difference between the upper and lower sensors is the thickness.

3.5 Mutual interference suppression

When two sensor heads are installed close to each other, they can be connected through ZX-CAL2 and the mutual interference suppression function can be enabled to alternately emit light and avoid crosstalk.

Laser safety and compliance

The ZX series laser sensor belongs to visible light semiconductor laser (wavelength 650nm, maximum output 1mW). Different models meet the following levels:

EN60825-1: Class 2 (diffuse reflectance, retroreflection, retroreflection) - Visible light wavelength, protection can be provided by human eye blink reflection, but cannot be viewed directly.

FDA: Class II (as above).

Safety operation requirements:

It is strictly prohibited to directly look at the laser beam or observe the reflected light through optical instruments.

The end of the laser beam path should be equipped with absorbing materials to avoid diffuse reflection to eye level.

The protective casing must not be disassembled, and repairs must be returned to OMRON.

The product is labeled with laser warning labels (yellow background with black symbols) and instruction labels.

Preheat for 10 minutes before use to stabilize the internal temperature.

Laser product labeling requirements (EN standard):

Class 2 products need to have the "Caution" label affixed to the body and indicate "Laser Radiation - Do Not Stare Into Beam".

The aperture label should be marked near the laser exit.

Common troubleshooting

5.1 Amplifier has no display or output

Possible reasons:

The power supply voltage is below 12V or exceeds 26.4V (allowable range is 12-24V ± 10%).

Reverse the polarity of the power supply (brown connected to 0V, blue connected to 24V).

The sensor head connector is not locked or the cable is broken.

The average frequency setting is too high, resulting in extremely slow response and mistaken for no output.

Troubleshooting:

Measure the voltage of the amplifier power terminal with a multimeter (should be between 19.2~26.4V, including ripple).

Check if the connector is properly inserted and try unplugging it again.

Reduce the average frequency to 1 or 2 and observe if the output changes.

5.2 Measurement value jumping or instability

Reason:

The surface reflectivity of the tested object undergoes drastic changes (such as alternating metal and black rubber).

Excessive ambient light (incandescent lamps below 3000lx are allowed, but high brightness halogen lamps may interfere).

Sensor head vibration or rapid temperature changes.

The linear output is not grounded with shielding, or the shielding wire is erroneously short circuited to 0V.

handle:

Use a line beam sensor (L model) to average the reflection difference.

Adjust the installation angle to avoid mirror reflection light returning to the receiver.

Increase the average frequency.

Confirm that the linear output ground (shielded wire) is grounded separately and not mixed with other 0V.

Use the interference suppression function of ZX-CAL2.

5.3 Misdetection of Shooting Sensors

Reason:

There are more than one object or unclear edges within the measurement width.

The transmitter and receiver are not aligned.

Camera contamination.

handle:

Use the teaching function to set appropriate thresholds.

Adjust the alignment bracket of the transmitting/receiving end and use the optical axis alignment function (light intensity display on the amplifier).

Clean the lens (see cleaning methods later).

5.4 Excessive temperature drift

The temperature characteristics of ZX series: Reflective type is ± 0.03% FS/° C (LD300/LD300L is ± 0.1% FS/° C). If the temperature change on site exceeds 10 ° C, significant errors may occur. Solution:

Perform zero temperature compensation (by setting the zero memory function through an amplifier and resetting it to zero after temperature changes).

Install the sensor in a constant temperature environment or use a heat shield.

Choose models with better temperature characteristics (such as LD30V).

5.5 Laser LED does not light up

Reason: The laser OFF input is activated (green line low level), or the laser is aging and damaged.

Inspection: Measure the voltage of the green wire to 0V. If it is at a low level (<1.5V), the laser will be turned off by an external signal. Open it or connect it to a high level. If it still doesn't light up, return for repair.

Maintenance and Cleaning

6.1 Lens Cleaning

If the front lens of the sensor head is contaminated with dust or oil, it will cause a decrease in the measured light intensity. Prohibit the use of organic solvents such as thinner, benzene, acetone, kerosene, etc. Correct steps:

Use a balloon (for camera lenses) to blow away large particles of dust, do not blow with your mouth (saliva corrodes lenses).

Dip a soft lens cloth in a small amount of alcohol and gently wipe it. Do not rub forcefully to avoid scratching the coating.

6.2 Battery and Storage

There is no battery inside the amplifier unit. The sensor head has no vulnerable parts. Long term storage should be in a dry, non corrosive gas environment.

6.3 Firmware Version Compatibility

When using the ZX-SF11 communication interface unit, the amplifier version must meet the following requirements: ZX-LDA11-N Ver.2.100 or above, ZX-EDA11 Ver.1.100 or above, ZX-TDA11 Ver.1.000 or above. Old versions may not be recognized. The version can be viewed through the Smart Monitor software.

Suggestions for replacing discontinued models

Some early models of the ZX series have been discontinued (such as the ZX-LD30V/VL, which can still be purchased, but the ZX-LT001/005/010/030 opposed models may be replaced by new models). Attention when replacing:

Maintain consistent or higher measurement range and resolution.

Replace the positive and negative reflection type with the same type (ZX-LD30V → ZX-LD30V subsequent models).

The amplifier unit ZX-LDA11-N/41-N can still be purchased, but if discontinued, the ZX-EDA series can be selected (compatibility needs to be confirmed).

The computing unit ZX-CAL2 and communication interface ZX-SF11 are still the current products.

If the sensor head is damaged but the amplifier is intact, the same model of sensor head can be directly replaced without reconfiguring the parameters (which are stored in the amplifier).