With the growing number of wireless instrumentation devices now availableCONTROL ENGINEERING China版权所有, you may have noticed that most of the offerings are toward the less-complex end of the device spectrum, things like temperature and pressure sensors. More complicated things like flowmeters have been slower in coming.
        The apparent method in this selection is that vendors are bringing out devices that are relatively inexpensive and have low power consumption控制工程网版权所有, and as such are suitable for battery powering. Suppliers are showing you that these sensors don’t need wires of any kind, neither data nor power. The problem is that the list of field instrumentation technologies suitable for battery powering is pretty short.
        Vendors have a very good handle on the power consumption characteristics of device radios. Once you’ve determined the amount of data to be transferred, the update rate frequency, and the amount of repeater trafficCONTROL ENGINEERING China版权所有, you can calculate the power need very accurately and then lay this out against your various battery options. The killer for a self-contained device is that the sensing technology also has to take power from the same batteries.
        Optimizing sensor power
        Radios gain their efficiency by sending data in a matter of milliseconds and then going to sleep between transmissions. For maximum battery life, the transducer technology has to match that quick action, but all don’t. Characteristics vary widely, but all don’t snap into action immediately. The transducer and its processor circuitry may need to stabilize after the power goes on before their measurement is final and ready to send. That may only be a few milliseconds as wellCONTROL ENGINEERING China版权所有, but when multiplied over the number of times it has to happen控制工程网版权所有, that can be an eternity relative to the battery life. Con