Sensor Design Engineering Services

Posted by Seta Davidian on Sep 26, 2016 11:48:16 AM

gauge.jpgServoflo, a premier supplier of pressure, mass flow, environmental sensors and micropumps,  is pleased to announce expansion of its design engineering services for custom sensor development. The objective is to be a primary resource for customers who require modification or customization of sensors and how they are integrated into product designs. Services include but are not limited to:

  • adding flex to a sensor
  • creating a custom flow path for mass flow sensors
  • adding Wi-Fi or BlueTooth™ capabilities to a sensor
  • adding a display
  • custom packaging enclosures
  • hybrid circuit design

flex.jpgThis one-stop solution provides customers with efficient and reliable design expertise without having to manage multiple vendors as well as streamlining assembly. Purchasing a complete solution saves customers money and time. Often, a bill of materials is reviewed and pressure is put on individual component costs. This strategy neglects the labor needed to inspect, integrate, and test various separate components such as a sensor element, cable, and package. A complete sensor solution can actually reduce overall bill of materials and labor costs. This sensor design strategy is also important for customers who may not have design expertise in these areas.

Specific application examples include:

  • Creation of a pressure gauge with display and enclosure
  • Hybrid circuit design to integrate a pressure sensor and electronics for better protection in a high temperature and high humidity environment
  • Adding a flex cable to a standard board level sensor to eliminate the assembly and testing steps at installation
  • Customized sensor calibration and output to meet a specific customer requirement
  • Design of a special flow path in a mass flow sensor for medical equipment
  • Design custom electronics to create a pressure or mass flow switch (or other environmental sensor)

If you have a special requirement you would like to discuss, please utilize the button below for fastest response.

  Discuss a custom solution

Topics: Ceramic Pressure Sensors, Pressure Sensors, Mass Flow Sensors

Key Factors When Selecting A Pressure Sensor

Posted by Seta Davidian on Jul 19, 2016 11:20:10 AM

presentation.jpgAt Sensors Expo, held this past June in San Jose, David Ezekiel gave a special show floor presentation titled Key Factors When Selecting a Pressure Sensor. This presentation was created for those new to pressure sensors.

Presentation highlights included a discussion about:

  • The advent of MEMs sensors and resulting new product features
  • New applications using pressure sensors
  • The huge number of manufacturers and models, each having slightly different features, accuracies and packages
  • The paradox of choice - how too many options results in selection errors and overall dissatisfaction

The presentation detailed how to narrow these choices by looking at the skill set in your organization, overall product & system requirements, and other factors such as time frame, second sources, and contact manufacturers.

By understanding the application basics, mechnical, electrical, and assembly factors, a user can then begin to narrow down the myriad of pressure sensor choices. For example, when should a user pick a lower cost unamplified, uncalibrated sensor over a calibrated and compensated sensor with more features but higher cost?

For new users of pressure sensors, it is easy to get caught in this paradox of choice and be oversold on a sensor with features that may not be needed. Take a look at the presentation, and learn about how to not fall into this trap.

dilbert.gif

As experts in pressure sensors, many times we have told customers to choose a lower cost solution based on their application requirements. We will never oversell you on features you do not need.

Key Factors In Selecting  a Pressure Sensor

Topics: Pressure Sensors

How to Choose an O-Ring for TR Series Pressure Sensor

Posted by Seta Davidian on Jun 2, 2016 3:36:10 PM

harsh media pressure sensorThe following is a short synopsis of a new application note for the TR Series harsh media pressure sensor.

The TR Series Pressure Sensor is a fully calibrated, back side pressure sensor for use with any media that is also compatible with silicon, glass, ceramic and solder. The TR Series is designed to be used with an o-ring, creating a face seal to the back of the sensor.

When designing an o-ring face seal, several environmental factors much be taken into consideration:

  • Temperature - What are the minimum/maximum temperatures for both operation AND storage? Does the temperature vary during operation or is it stable?
  • Pressure range - Identify the minimum and maximum pressures. Are they positive, negative or both? Fluctuating or constant?
  • Media - Identify what is in your media. What are the exposure conditions (temperature, pressure and concentration of chemicals in media). The backside is exposed to the harsh media while the front is exposed to another environment. This front side must be protected from harsh media.

Some o-ring features for users to decide include material and geometry options.

  • Material - Different o-ring materials have different temperature handling abilities. A soft o-ring will provide a very compliant seal but many not seal well at high temperatures. A hard o-ring would seal well at high pressures but may induce high packaging stresses.
  • Geometry options - O-ring size (both OD and cross-section) must ensure that media will not leak at the minimum and maximum pressure and operating temperatures.

The bottom line is to test with static and dynamic analyses in addition to customer verification, as each application is a unique combination of temperature, pressure and media.

Access the complete application note

Learn more about the TR Series

 

Topics: Pressure Sensors

FSP1000 Ultra Low Pressure Sensor

Posted by Seta Davidian on May 17, 2016 2:33:17 PM
fsp1000-header.jpgServoflo is pleased to announce the FSP1000 Ultra Low Pressure Sensor. This sensor is designed to measure ±1" H2O up to ±2" H2O. With a compensated temperature range of -5°C to 65°C, the FSP1000 has a fast response time of 5 milliseconds and has an I2C with 12 bit resolution and linear voltage output of 0.4 to 2.4V. The supply voltage is 3.0 - 3.6 VDC.
This sensor has a flow through design and can be placed in any orientation without affecting performance. The pneumatic flow resistance is less than 95 ml/min at 500 Pa. The sensor is fully compensated for altitude.
 
Typical applications include but are not limited to medical, HVAC, instrumentation, critical containment and more. 
 
Download Low Pressure  Product & Pricing Guide
 
 

Topics: Pressure Sensors

Mass Flow Sensors for Anesthesia Machines

Posted by Seta Davidian on Apr 7, 2016 1:23:50 PM

Mass Flow Sensor FS4008General anesthesia machines typically deliver a cocktail of gases to a patient to ensure sedation during surgery. Nitrous oxide (also known as laughing gas) and other gases are mixed with oxygen and delivered to the patient. The buffer area shown in the drawing below is where the combination of nitrous oxide and oxygen is mixed together. Here, the anesthesiologist needs to be aware of the mix of gases that is appropriate to the patient. At times, the combination needs to be adjusted depending on patient requirements.

To control the level of oxygen and nitrous oxide delivered to the buffering section of the anesthesia machine, it is necessary to measure the volume of each gas. In the drawing below, the FS4008 mass flow sensor is shown as a method to measure and monitor the various gas levels. The FS4008 comes in various flow ranges from 0-10 SLPM up to 0-50 SLPM. Available outputs include linear voltage or digital RS232 or RS485, allowing for the FS4008 to be easily integrated into a control system for the various gases. The flow channel diameter is 8 mm, and there are exchangeable mechanical connectors for ease of installation (BSPT thread and one-touch connectors).Slide2.jpg

 

At the delivery location of the gas mixture to the patient, another flow measurement point is needed. Here, the FS6022 mass flow sensor can play an important role in ensuring gases are delivered to the patient and then subsequently exhaled. Because the FS6022 has bi-directional measurement capability, it is ideal for use in the scavenging portion of the anesthesia machine, which expels the used gas from the patient's lungs.  For details about the FS6022, you can also review our blog post: Mass Flow Sensors for Medical Ventilators

In summary, measuring and monitoring mass flow of gases in anesthesia equipment is a critical part of patient comfort and surgery success. Not only is it important to measure the mix of anesthesia gases, it is also vital to measure delivery of the gases to the patient.

You can learn more about mass flow sensors here or download our mass flow product & pricing guide.

Download Mass Flow  Product & Pricing Guide

 

Topics: Mass Flow Sensors

New Controller & Kits Drive 4 mp6 Micropumps Simultaneously

Posted by Seta Davidian on Apr 5, 2016 1:18:43 PM

Servoflo is pleased to announce the availability of new evaluation kits and a new driver board for the mp6 micropumps. The new Quad Series lets users drive up to 4 pumps simultaneously. This means that a user can design an electronics system using 1 mp6-QuadOEM to drive 4 mp6 pumps. Even more exciting, the new technology lets users increase the pumping rate of the mp6-air to up to 42 ml/min, since frequencies can be increased to 800 Hz as opposed to 300 Hz for the original mp6-oem. Pumping rates for liquids using the mp6 remains at 7 ml/min.

mp6-controller-overview-small.jpg

Here is a summary of the new items:

mp6-QuadEVA: This kit comes with the QuadEVA board, 4 pumps, mini USB cable. An air version (mp6-air-QuadEVA) is also available. 

mp6-QuadKEY: This evaluation system has a detachable mp6-QuadOEM, and uses Arduino as an interface. An air version (mp6-air-QuadKEY) is also available.

mp6-QuadOEM: New controller can be used by itself for integration into production. Parameters can be changed via I2C. 

To help understand the various performance differences between controllers, the 2 charts below describe the pumping performance for water and gas.

controllers-gas-air-performance.jpg

 

To fully understand the different options, we suggest you start by reviewing this tech note, Controller Overview.

Then, we also suggest reviewing the product manuals:

mp6-QuadEVA

mp6-QuadKEY

mp6-QuadOEM

To get pricing on these evaluation kits, you can simply email us at info@servoflo.com or you can download the Micropump Product & Pricing Guide.

Micropump Product & Pricing Guide

Topics: Micropumps

Driver Reference Design for mp6 Micropump Now Available

Posted by Seta Davidian on Mar 7, 2016 12:57:46 PM

mp6 micropumpServoflo is pleased to announce the availability of a driver reference design for the mp6 micropump. Written by Microchip, the application note describes the implementation of a basic circuit for driving the mp6 with flow control for a fluid delivery system.

The application note includes a description for a control board, a high voltage driver board, and the mp6 micropump. The control board provides the adjustable voltage and frequency control signals to the high voltage driver board. Then, the high voltage driver board delivers the boosted signals in specific waveform on multiple output channels with adjustable peak-to-peak voltage (VPP) and frequency to the piezoelectric micropump. The demo can supply a maximum of 250V of VPP and a maximum frequency of 300 Hz. A bill of materials is included with the application note.

mp6 micropump control design

The mp6 micropump is designed to pump 0-7 ml/min of fluids and up to 18 ml/min of air/gas. Applications include medical devices, drug delivery, call 

Download the complete application note

Micropump Product & Pricing Guide

Topics: Micropumps

Hybrid Circuit Technology by Metallux

Posted by Seta Davidian on Feb 29, 2016 11:41:05 AM

chip-on-board-small.jpg

Metallux SA, based in Switzerland, not only offers ceramic pressure sensors but also thick film technology hybrid circuit design and manufacturing, i.e  screen printing on ceramic, FR4, Flex, steel, aluminium nitride, sapphire, etc. Metallux SA also offers the capability to integrate electronic components such as IC's, resistors, capacitors, etc.

Why use a hybrid circuit?

  • High temperature demands. Circuits can be designed to withstand more than 85°C or for harsh environmental conditions such has high humidity.
  • Low & medium power requirements around 2-3 kW. Ceramic is a very good heat dissipator.
  • When trimming is required. It is possible to trim the screen-printed resistor on circuits with electronical components to adjust a voltage, current or frequency output.
  • A smaller size is needed
  • Enhanced security. It is very difficult to reverse engineer a hybrid circuit.
  • Need to use resistors and conductor tracks to create a power source (such as from millawatts to 3-3 Kilowatts)
  • More resistant to shock & vibration

From design to screen printing to assembly, Metallux provides a complete hybrid circuit solution for their customers. Some examples of their capabilities include:

  • Superior manufacturing area with 3 cleanrooms
  • Multilayer hybrid circuits with integrated trimmed resistors (from mohms to Gohms)
  • Active/passive SMT, from 0201 size to BGA and µBGA
  • Chip & wire: die attach, wedge & ball bonding, encapsulation, on all kinds of substrates
  • Flip-chip: solding & epoxy 
  • Finishing & encapsulation with conformal coatings, epoxy & silicone resins

As an example, here is a real world hybrid circuit design by Metallux:

custom-sensor.jpgSilicon pressure sensor for home boiler: A thick film hybrid circuit was designed for better stability in a harsh temperature and humidity environment. The stable and rigid substrate had the die pressure sensor glued onto it. The coefficient of thermal expansion (CTE) of the Alumina is lower compared to a standard PCB.

To discuss how hybrid circuit technology can help you, please contact us.

Contact Us About Hybrid Circuits

 

Topics: Ceramic Pressure Sensors

Mass Flow Sensors for Medical Ventilators

Posted by Seta Davidian on Feb 23, 2016 9:39:29 AM

A ventilator uses pressure to blow air or a mix of air and oxygen to a patient. This blog post describes how the FS1015FL (shown on the left below) and FS6022 (shown on the right below) mass flow sensors are used in medical ventilators. These mass flow sensors are members of the new Siargo line which Servoflo is now offering.

mass flow sensor fs1015clmass flow sensor bi-directional bidirectional fs6022 

Both of these mass flow sensors use a MEMs sensor chip based on the calorimetric principle. The chip is packaged in a special way to receive laminar flow. The sensor chip has a micro heater and a pair of sensors upstream and downstream. When gas flow passes over the sensor chip, it brings the heat from upstream to downstream. Mass flow rate is calculated by measuring the temperature differences from the upstream and downstream sensors.

The illustration below shows how the mass flow sensors are installed inside the ventilator. The inlet air and oxygen is mixed and delivered to the buffer and valve. The FS1015CL sensors are calibrated for either 0-100 SLM or 0-150 SLPM. The flow rate of air/oxygen is measured to ensure the correct amount is delivered to the patient. The FS1015 has a 5V supply with a linear voltage output or an I2C interface. Standard ISO 15 mm medical connection is available. 

mass flow sensors in medical ventilators

 

The FS6022 is a mass flow sensor with a bi-directional option. Ranges include up to 250 SLPM or 300 SLPM. Having a standard voltage output, the bi-directional model provides a 2.5 to 5V output for the positive full-scale flow rate and 2.5 to 0 V for the negative flow rate.  Here, the FS6022 is used to monitor the inhalation and exhalation of the patient. 

These sensors can be sterilized in medical liquids.

Review:

We have a recently updated mass flow sensor product & pricing guide which includes these models. 

Download Mass Flow  Product & Pricing Guide

Topics: Mass Flow Sensors

Monitoring HVAC Filter & Fan Units With AMS5105 Pressure Sensors

Posted by Seta Davidian on Feb 22, 2016 11:40:26 AM

ams5105.jpgAnalog Microelectronics has an application note discussing how to monitor HVAC fan and filter performance using the AMS5105 pressure sensor. The AMS5105 is a board-mount, compensated and calibrated pressure sensor with an analog ratiometric 0.5 to 4.5V output along with two discrete, programmable logic switching ports. For each switching port, the switching function, threshold, hysteresis and delay can be set individually. Having low differential pressure calibration from 100 mbar down to 5 mbar, the AMS5105 is ideal for fan and filter monitoring systems.

Included with the application note are the following four application examples with circuit drawings :

  1. Simple HVAC Filter Monitoring System With Pre-Warning - Here the switching ports are programmed as normally-open and hysteresis is set to 5% of the calibrated pressure range. 
  2. HVAC Filter Monitoring System with a 24V Supply and Robust Outputs - Similar to the first example but includes details what to do if only 24VDC is available as a supply.
  3. HVAC Filter and Fan Monitoring System With Diagnostics - Learn how to set up the switching ports for normal and filter replacement
  4. HVAC Monitoring System with Diagnostics Measured at an Orifice - Similar to #2 but measurement is taken across an orifice to protect the sensor from contaminants. 

Here is the circuit drawing for item #1, Simple HVAC Filter Monitoring System With Pre-Warning:

hvac-filter-monitoring.jpg

As you can see, this application note gives great details on how to use the AMS5105 for HVAC filter monitoring. We hope you find it as a useful tool that can be applied across many different applications.

Learn more about the AMS5105

Download the complete application note

Download Low Pressure  Product & Pricing Guide  

 

Topics: Pressure Sensors