When was the last time you thought about batteries? Probably when a battery-operated device stopped working suddenly in the middle of something important, right? Yet many wireless devices in your home and around the plant where you work are powered by batteries, and you have come to rely on those devices. Over the next few weeks, we’ll take a close look at batteries used in the plant to power wireless instrumentation.
When planning the purchase and installation of new wireless instrumentation and designing the network, installation, and storage of these devices, it pays to be aware of the features and settings that impact battery life. It is not just how much power a device will need to operate, but also what kind of demand there will be on a battery and how the wireless network is set up. Regardless of the wireless instrumentation protocol selected, a poorly designed system will impact the life of the battery.
Things to consider
A basic list of what should be considered when choosing wireless power options for your wireless applications includes the following:
- Measurement type: in wireless instrumentation, the battery is entirely responsible for providing the power necessary to transmit the information wirelessly and power the sensing element along with any other features like LCD screens on the device. It is very common that the sensing element for most types of measurements consumes more power than the other needs of the transmitter. An example of this is wireless LEL (Explosive Gas) sensors. When considering battery life, be sure to consider the measurement type and frequency of measurement. It is common for manufacturers to slow down their update rates for specific devices to publish a long battery life.
- Ambient local temperature: Batteries used or stored in extreme ambient temperatures, or locations with large temperature differentials can expect these batteries to have a shortened useful life as extreme ambient temperatures can impact battery performance if not considered during the planning and installation of the sensors.
- Network design: Most industrial process facilities are made up of a variety of infrastructure densities. This can range from a highly dense infrastructure of pipe racks, heat exchangers, tanks, etc., to light density around the tank farm or storage facilities. It is important to consider the performance of your selected wireless protocol to ensure that it will provide reliable coverage and battery performance in all these environments today and after possible future plant expansions.
- Update rate: Like all battery-powered devices, the more you use it, the more power you will consume. Most battery-powered devices have a published battery life, which is always based on a set of standard usage criteria. For instrumentation, update rate is one of the most important contributors to battery performance. It is common for wireless instrumentation providers to publish long battery life based on a very long update rate (>1hour). These long update rates may be acceptable for the first year, but history suggests that most facilities require faster update rates to support performance optimization efforts. Will your selected protocol be able to handle your update rate needs today and in 5 years?
Planning it right
When planning the purchase and set up of wireless transmitters across your facility, look closely at the wireless network that will support them and the features and settings required by each application. You may find that the wireless protocol and instrument, which appears to meet your needs on paper today, actually lacks the capabilities to support your needs for the future.
Visit our website to learn more about Emerson’s battery powered wireless transmitters.