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Miniature Sensors With Monumental Capabilities

Application requirements solved by miniature optical sensors.Application requirements solved by miniature optical sensors.The requirement for miniature optical sensors to meet the demands of medical and semiconductor automation equipment often exceeds the capabilities of standard self-contained optical sensors. In some cases, other industry application requirements can be best solved by these same miniature optical sensors with advanced capabilities. So, what do these optical sensors offer that makes them so much better?

Application requirements solved by miniature optical sensors.Applications

Let’s begin with some of the applications that require these capabilities: medical applications, such as lab-on-a-chip microfluidics, liquid presence or level in drip chambers or pipettes, turbidity, drop detection, and micro or macro bubble detection, to name a few. Semicon applications include wafer presence on end-effectors, wafer mapping, wafer centering, and wafer presence in transfer chambers. Other applications that benefit from these sensors include packaging pharmaceuticals, detecting extremely small parts, and spray detection. In addition, these sensors are frequently used in customer-specific designs because they can be customized for specific applications.

Application requirements solved by miniature optical sensors.These sensors require an amplifier which sometimes is not popular with design engineers. They are associated with additional cost and extra work during installation; however, the remote amplifier offers real advantages. The optical function is separate from the control unit which allows it to be incorporated into an extremely tiny sensor head. Since the LEDs are mounted in the sensor heads, we now have a small wired connection back to the amplifier. Unlike fiber optics, this wired connection to the emitting LED and receiver allows for very minimal or no bending radius because of the cable in use.

Features

The new generation of amplifiers offers tremendous flexibility with advanced features, including:

    • OLED displayoptical sensors.
    • Intuitive menu structure
    • LEDs for status, communication, and warnings
    • Teaching/Parametrization
    • Single-point, two-point, window, dynamic, and tracking operating modes
    • Multiple teach modes: direct, dynamic, external, automatic and I/O-Link
    • Selectable power modes
    • Selectable outputsminiature optical sensors
    • Selectable speed settings
    • Auto-sync up to 8 amplifiers
    • Configurable delays and hysteresis
    • Compatible with existing all sensor heads

The sensor heads or optical heads come in a wide variety of housings, including the ability to customize them to meet specific requirements. And they are available in small precision LEDs, photodiodes, phototransistors, and complete laser modules according to a patented manufacturing process. Due to the high optical quality, additional lenses or apertures are no longer necessary.

Application requirements solved by miniature optical sensors.A multitude of special characteristics completely differentiates these sensors from the products made by standard optical sensor manufacturers. The range of products includes extraordinary miniature optical sensors as standard products, optimally adapted customized solutions, and precision optoelectronic components, such as LEDs, photodiodes, and laser modules. High optical quality, and unique modular designs, in connection with the greatest possible manufacturing flexibility, guarantee solutions that are exactly adapted to the respective problems and needs of the users.

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Add Safety and Accessibility With Remote Amplifiers

Why did the sensor cross the road?

To work remotely, of course.

Even sensors are working remotely these days, and some have good reason. Many applications dictate that the sensing element be placed remotely from its associated electronics. Let’s looks at a few common examples of this.

This may be for safety’s sake, such as in oil and gas applications where housing the bulk of the electronics away from a hazardous area reduces the likelihood of an electrical discharge, or where there are environmental concerns, such as temperature or vibration. By placing the majority of the electronics safely away, only the minimal number of components are subjected to the extremes.

Another good reason for remote placement is accessibility. In some cases, for example, the sensor must be mounted in a difficult to reach place, and having remote electronics installed in a more accessible location allows for easier access for the needed periodic re-teaching, adjusting, etc.

Separate electronics are also used when the sensing element needs to be designed into a very tight space. These very small sensor elements are likely to be customized to fit into a device directly, often leaving no room for the remainder of the electronics.

Remote placement is typically used out of necessity, but it doesn’t have to limit sensor capability or performance.

A typical amplifier with jog button, selector switch, and display.
Typical amplifier with jog button, selector switch, and display

Separately housed electronics, known as amplifiers, can do more than just house the electronics that support the sensing elements; they also provide a way to configure the sensors through buttons and displays. The amplifier delivers the smart features that larger sensors possess, without increasing the sensor size.

Let’s take a look at an amplifier designed to work with the micromote photoelectric sensors.

Micromote photoelectric sensor with 2mm diameter.
Micromote photoelectric sensor with 2mm diameter

Micromotes are extremely small photoelectric sensors that direct a very tight beam of collimated light at a target. The light emission is specifically engineered for the application, either attenuating or refracting as it interacts with the object to be detected. Many of these applications involve detecting very small bubbles in a stream of fluid, micro-bubbles that are smaller than the human eye can detect.  Others may be used to detect the edge of a microscope slide or count very small drops of liquid.  They are precision engineered to detect small objects in small spaces.

The amplifier will receive a power source, and in return it will provide power to the sensing element. But beyond the supporting electronics, what else might a good amp do?

    • Provide a choice of output types (PNP/NPN/Analog/NO/NC)
    • Supply an adequate frequency response for the fast counting of objects
    • Use LED indicators to help troubleshoot connections and warn of unstable signals
    • Provide on/off signal delays (pulse stretching) for those super fast applications
    • Allow the signal hysteresis to be adjusted to suit the application
    • Provide a way to lock the set parameters from inadvertent changes
    • Offer an alarm output if the application is out of specified limits
    • Include a display to navigate through the menus and to display signal strength when operating
    • Teach the application through the use of selector switches
    • Deliver auto synchronization

So, the next time you have a demanding application that requires a sensor to work remotely, consider a premium amplifier — one that not only supports the sensing element, but provides the smart features that today’s best sensors offer. You just might find that working remotely has many advantages, including a more integrated final product, which is more accessible to tune, and with additional features.