Next Generation Electronic Pressure Switches

Barksdale: A leading manufacturer of pressure switches recently analyzed their existing product portfolio as well as upcoming requirements in diverse markets. As a result the new BPS3000 series of electronic pressure switches is now presented, featuring a forward-looking unique “all-in-one” design.

Machine tools, steel mills or wind energy – whatever we talk about: pressure switches have applications for monitoring or automatic control on all five continents – and even on the ships between them on the seas. This wide range of potential applications is a challenge for all product managers and their colleagues in development and design departments. However, when new ideas, new applications, new requirements, new components and technologies finally call for the design of a completely new product, it is time for a truly innovative next generation.

Barksdale GmbH, located close to Frankfurt am Main, Germany, belong to the small group of leading manufacturers in the field of pressure switches. After numerous communications with existing and potential customers as well as detailed market analyses they have now released a totally new set of electronic pressure switches called Series BPS3000.

Display and Controls
Not only because of its appearance, material or selected colour but mainly because of its functionality, the outer design of the new electronic pressure switches may be prize worthy. A slightly chamfered and curved head of the electronic pressure switch is used for both display and operator panel. The diameter of the pressure switch is less than 40 mm.

Featuring 9 mm high 14-segment LEDs, good readability of the four-digit alphanumeric display is achieved even from the side. The status of the switch or any alarms is displayed by additional LEDs. Even if the device is mounted upside-down easy readability of the display is ensured by internal software.

Any set-up for operation is implemented by a kind of keypad which is formed by three fully integrated buttons, providing excellent haptic feedback (not to be compared with conventional membrane keypads). The set-up menu for operation strictly follows the widely known popular standard published as VDMA Standard Sheet 24574-1. The operating unit (head) of the pressure switches may be turned by 320 degrees without changing the position of other parts like electrical or mechanical connections. This is achieved by the rotatability of the process connection (also by up to 320 degrees). Over and above this flexibility, the pressure switch in its entirety features protection class IP65/IP67, including the operator panel. The total height of the device is slightly less than 100 mm.

Measurement Ranges and Connections
Six ranges cover the region from 0 … 10 bar to 0 … 600 bar. Up to 400 bar ceramic pressure cells are in use combined with FKM seals. Temperature is compensated in the range of -10 °C … +70 °C. Employing 12 bit digital resolution repeatability is specified as
±0.1 %FS.

Piezoresistive pressure cells are in operation at the 0 … 600 bar range. As an option they can be supplied for other ranges too. The BPS3000 series pressure switches are available with the popular G1/4” female or NPT thread or even flush process connection for pasty media e.g. in lubrication applications. Special versions for CETOP Standard process connections are already in preparation.

Switching Functions and Output Signals
In addition to the programmable stand-by mode of the transistor output, switching hysteresis can be set up to 125 % of measurement range while a switch delay may be set up to 9.9 seconds. Simply by using the keypad, even windows of operation are easy to set up. An analogue to digital conversion rate of 1.000 Hz gives reliable input for switching frequencies up to 100 Hz as specified.

Besides their switching functionalities, the BPS3000 series pressure switches provide pressure transmitter functionalities by supplying analogue output signals in the format 4 … 20 mA or 0 … 10V. These outputs are scalable between 25 %FS and 100 %FS. Operational flexibility is one of the real strengths of the new pressure switches from Barksdale GmbH.

EMC – even for Far East Conditions
Because of the extremely diversified fields of application, during development an eye was continuously kept on EMC. “If we talk about EMC we do not think of these friendly kinds of standards within the European Community,” explains Jürgen Bayer, Product Manager for the new series pressure switches at Barksdale. “We rather think of applications outside of our well controlled EMC conditions as found in European machine industries. Typically such applications are located in steel mills or power plants where for example high power walky-talkies are in use quite frequently.” In plain text: we cannot specify the actual high level of immunity of the new BPS3000 series pressure switches that can optionally be achieved by the tests listed on the Standard Sheet with reference to our tame European EMC Standards. They are built not only in conformity with these standards but also to cope with even much harder interference conditions in real applications.

Supply voltage is specified in the range of 15 … 32 VDC at max. 50 mA current consumption (without load). Of course the design follows European regulations regarding CE, RoHS and others. On top of this Barksdale are going to have approvals for the US Markets (UL) and the Canadian Markets (CSA).

Markets
BPS3000 series electronic pressure switches are designed for a huge range of applications. At the top there are applications in manufacturing systems engineering (e.g. hydraulics, cooling, lubrication, compressors etc.) followed by applications in the energy sector (e.g. hydraulic power packs, steering systems in wind turbines etc.) and steel mills (e.g. monitoring lubrication systems). Applications inside the wet areas of automated machining centres still present real challenges. However, in this environment of workpiece machining the new pressure switches will perform extremely well, because the materials for control elements as well as the complete housing design are made to resist all sorts of cooling fluids which are in use there.

Prospects
Features and design of the new BPS3000 series electronic pressure switches are the result of innumerous talks with customers and other forms of market research. With the “all-in-one” concept in mind, they provide a number of functionalities which until today are only being found in different individual products. With its specific design, the BPS3000 is the first member of a larger family of Generation 3000 products that will be released in the near future for temperature, level and flow.

Whilst the new series contains a unique number of functions and features extremely high flexibility in use, it does not yet cover every possible application.
However, this is not an issue, as another of Barksdale’s strengths is the ability to provide custom-designed variants and we are ready and waiting for these challenges.

About Barksdale GmbH:
Barksdale GmbH and Barksdale Inc. are part of the globally acting Crane Co. holding, Stamford, Connecticut, USA. Core competencies like pressure, temperature, level and flow are based in the production centres in Reichelsheim (near Frankfurt/Main) and Los Angeles. Representatives all over the world take care of the individual and regional requirements. The focus of development is on sophisticated products with high and safe functionality to be used daily in mobile and stationary hydraulics, utility vehicles and industrial applications.