Latest Level Measurement Presentation

In this final chapter on level measurement, I will discuss equipment that is not commonly used but plays a significant role in industrial applications. This equipment typically functions primarily as level indication limits, meaning it has digital outputs such as power system, field system, or simply a local indication. Furthermore, it is usually built to last for demanding process applications or situations where analog or precision measurements are impractical.

These devices are generally of the blind or non-local type, as they can also be found in places that are not easily accessible.

SW of Two-Point Level

This digital output device can assist with level measurement, acting solely as a contact output and providing only two valid indications: one for ON and one for OFF. It can be used to activate and stop a suction pump or a silo where the material being measured is highly corrosive. Additionally, it features a contact that activates a horn, serving as an alarm if desired.

This is a clear example of a level switch for a silo, where the sensor element generates a field that is disturbed by the external environment and through its amplification electronics is able to generate the activation of a control contact.

Through this image you can see, according to its manufacturer, how to install this device on the wall of a silo, a pond or a pool drain.

We need to keep in mind that the control outputs must be 120 VAC, standardized in order to access a PLC or DCS that has the possibility of activating a control output for what the system configurator proposes.

The following equipment is of the SW pressure type

This means that when the level of a material to be measured rests on the contact surface or detection plate, it can internally activate a contact as a control output again.

In this case, as in all others, it is clearly defined that these are devices that only activate contacts, a digital output, NEVER ANALOG.

Example of a level switch with a detection surface: the material reaches the level of the sensor face and this activates the output contact.

The same sensors but with the application of SW for measuring the level in the pond.

Application of level software for conditions where internal measurement is not possible due to the aggressiveness of the process, such as toxic gases, high pressure, high temperature, etc.

This system allows us to detect a level that has a highly variable process feed and load in large volumes. It can be installed on the side where the feed material does not move to the tank. It also provides a digital output and has an external power supply that allows its propeller to rotate. When it encounters resistance to movement, it will force, with its torque, a contact mechanically attached to this device.

Each of the examples shown above are pieces of equipment that are not commonly used but have a very frequent application, due to their cost, easy installation, robustness, etc.

It is always important to keep in mind that when performing maintenance on any measuring equipment, the manufacturer's instructions for installation, maintenance, and operation must be followed. This will ensure a long lifespan, fulfilling the stated performance and preventing harm to people, the process, or the environment.

As an instrumentalist, taking care to do a job well should be the first way of working.

Any questions, please email: hcarrasco@instrumentacionycontrol.net

Twitter: @instrumentacion

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