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.
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.
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.