Figure 3: The Honeywell's 20PC series of liquid media compatible pressure sensors offer many options for pressure range, package style, and digital/analog outputs
Reliability of supply also is important to designers. sensor manufacturers should have a global presence to support design and production requirements. As an example, European designers often will develop a product that requires several modules or subassemblies that are typically outsourced to electronics manufacturing service (EMS) companies in different parts of the world. The modules or subassemblies are then shipped back to the manufacturer in Europe for final assembly.
Emerging technical trends
Medical device engineers also require suppliers to provide product support for emerging technical trends. A few examples include digital interface options and single-use sensors. sensor manufacturers are offering digital interfaces, particularly I2C outputs, for a few reasons. A digital I2C output allows designers to eliminate signal conditioning circuitry from the printed circuit board (PCB), which saves board real estate and costs related to the signal conditioning. It also reduces the amount of copper traces and wires for a further cost savings. The fewer components on the PCB allow for miniaturization.
The on-board signal conditioning provides the sensor's compensation, calibration and amplification. This delivers higher accuracy and reliability, which contributes to patient comfort and quality of care. It also lowers the overall cost of ownership for the medical hospital or clinic. This can benefit a wide range of applications from dialysis machines and infusion pumps to incubators and respiratory equipment.
There is also a growing trend for single-use sensors in applications such as infusion pumps to eliminate the need to clean areas that come into direct contact with medicated or patient fluids. However, medical practitioners should take into account the reliability of single-use sensors as the performance of the sensor can be a determining factor in how well the equipment performs for the patient.
Cross contamination is a big concern in systems intended for single-use, when the sensor is not changed with every patient when it's supposed to be. This is especially true for devices used with patients with illnesses such as HIV/AIDS, the bird flu and Legionnaire's disease that are transmitted by bodily fluids. While medical device manufacturers recommend using one sensor per patient when using single-use sensors, there is the risk of multiple use at clinics in areas that also face budgetary issues combined yet with fewer regulatory controls.
About the author
James McKenna is Product Director in EMEA for the Pressure and Thermal product portfolio of Honeywell Sensing and Control, a manufacturer of sensors and switches within the ACS Strategic Business Group. More information about Honeywell and its technologies can be found at http://sensing.honeywell.com/.
Courtesy of EETimes Europe
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