In the month of April, we began a “How-to-Guide” to help you select a Load Cell highlighting the critical elements you should consider. In our May’s newsletter we continued our story by focusing on the important considerations when selecting a Torque Sensor. This month we continue our discussion of the “How-to-Guide” series on one of the most popular transducer types, the Pressure Sensor and the critical variables you should consider when selecting one for your application. Please bear in mind that there are a lot of variables to consider and we could have easily written a lengthy paper on this topic, but we want to highlight the most critical elements. We strongly believe in self-education and hope that this discussion further expands your understanding on this topic.

Step 1
First determine that you want to measure pressure. Pressure Sensors are designed to monitor the changes in pressure for fluid and gas applications. Do you want convert pressure into an analog output? The output of your Pressure Sensor is going to be one of the most critical questions you’ll face. Your options will vary between low (mv/V)/high (VDC) voltage analog, current, digital and wireless output. For example, if you select a low voltage analog output, you’ll have a faster response time and a wider temperature range and you’ll find fewer suppliers that can provide the instrumentation to go along with your Pressure Sensor. Going digital will provide options such as RS232, CAN Bus, or USB, but the number of suppliers offering these options will be limited.

Step 2
The cost of the Pressure Sensor will of course vary greatly depending on all of the requirements you may have. A low or high price should not be an immediate qualification/disqualification factor. Make sure you ask about the materials, process used, and support that each manufacturer provides. Designing within your budget constraints is going to be key (of course) but make sure you are fully aware of what you’re gaining/sacrificing with a low/high cost.

Step 3
If you’ve clearly defined your application, this should be a fairly simple decision. If you select the right manufacturer, they will be able to work with you with innovative approaches that keep the project within your means. Specifying your application requirements up front will help minimize the number of head aches you’ll face further down the line with your project. You may want to consider using snubbers or some form of protection for your Pressure Sensor if your application includes Water Hammer characteristics. Application examples include: process control, automotive racing, or volume control in any fluid application. We’ve provided an illustration on some of these Pressure Applications here.

Step 4
After you’ve determined that you want to measure pressure, define the type of pressure you want to measure – gage, absolute, differential. What type of fitting (miniaturization) will you have (Male, female, flush mount, semi flush)? Similar to selecting a load cell, be sure to select the capacity over the maximum operating pressure. Also be sure to define your cable termination (Cable, Connector, Built in quick disconnect) and specification requirements (output, burst pressure, required excitation, nonlinearity, hysteresis, creep, bridge resistance, etc.) Environmental conditions should also be considered as well. This includes your temperature range or corrosive chemicals that your Pressure Sensor would be exposed to.

Step 5
If you need an instrument for your application, select the instrument the same time you select the Pressure Sensor. This will help you avoid any chances of non-compatibility. Don’t forget to purchase system calibration with your order. This integrates your sensor and instrument as one system. Don’t forget, it is important to select the right sensor provider. Your sensor provider should have the knowledge and experience to support your long term needs.

Remember, these tips are guidelines to help point you in the right direction when selecting your sensor. It is very important to find a sensor provider that has the experience to support your needs. Find out if the company has worked with similar applications in the past. If it is a completely new application in which there is no precedence, select a company that is known for taking on these new challenges and would be able to work with you every step of the way from design to manufacturing and implementation. If do you require a nonstandard product, keep in mind that your expected delivery time and cost will increase.