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How to Program a Switch for Manual Reset

Compact Low Differential Pressure Switch with Manual Reset, Series 1900MR

Several applications require manual reset switches, which are switches that need to be physically reset by an individual for a process to continue or restart. A manual reset is often needed when an area has to be inspected prior to equipment restart. This can help to ensure the safety/inspection of both equipment and other individuals in the area.

Some switches have a mechanical manual reset (such as the Dwyer Series 1900, 1831, and 1800). However, there may be a need to have a manual reset for applications beyond what these switches are designed for. If a pump is allowed to run with a clogged filter, for example, this may severely damage the pump. Continue reading “How to Program a Switch for Manual Reset”

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Velocity Measurement and Environmental Effects

Differential pressure measurement can be beneficial in a wide variety of building automation system (BAS) applications.

One of these applications involves determining if a filter in your system needs to be cleaned or replaced. Filter health can be established by monitoring the pressure on the primary and secondary sides of a filter. A clean filter will typically have a baseline differential pressure generated as air flows through it. As the filter becomes dirty, this differential pressure increases.

When using a mechanical flow sensor, such as a pitot tube, differential pressure can also be used to determine flow velocity and volumetric flow. Continue reading “Velocity Measurement and Environmental Effects”

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Benefits of Using Current Switches/Transformers

Motors are used for numerous industrial processes, be it moving air with a fan, pumping water with a pump, or driving a mechanical process. It is important to know when motors are not operating properly or require maintenance.

Many installations rely on a sensor or instrument used for the primary process, such as the use of a pressure transmitter to verify system pressure in a duct or the use of a flow transmitter to verify flow in a pipe. When errors or loss of pressure/flow are indicated, maintenance personnel may be dispatched to remedy the issue. However, this method does not indicate the root cause of an issue. Relying solely on primary process instrumentation opens the door to an unforeseen, possibly catastrophic situation. Continue reading “Benefits of Using Current Switches/Transformers”