Wireless Sensors: The Data You Want
By Aaron Hand, Managing Editor
在某些地方使用有线传感器并不实际，然而制造厂商对于数据点的检测需求却与日俱增。在美国威斯康星州的Waukesha Machine& Tool公司在CNC的工具加紧装配过程中，若用有线传感器来持续跟踪托盘之间缓慢的相互作用要求是很难达到。 “我们的客户需要一个无线压力监测系统，因为他们需要在任何给定的的时间内一台机器上运行多个托盘。”Waukesha Machine& Tool的设计师Kyle Spuhler说到。
对于机械制造商，无线传感器可以满足客户需要的这种灵活性。“对于一个设备供应商面临的困难是--我需要将传感器放在哪里才能监测到客户需要的数据？”汉森说，“在获得客户的同意后，他们会从布线或从机器的I / O接口处着手。如果不经协商直接布线交付给客户的话，难免会有错误的地方。”
In our lives and in our jobs, we are inundated with data. At Rockwell Automation's Global Machine Builder Forum last month, Jeff Reed, vice president of Cisco's Unified Access Business Unit, warned of the "zettaflood" of data—not gigabytes, terabytes, petabytes or even exabytes, but zettabytes. It's no wonder, then, that the mere mention of a system's data-gathering capabilities can turn machine operators running the other way.
"People are inundated with data now," agrees Todd Hanson, director of wireless solutions for Honeywell Sensing and Control (www.honeywell.com/sensing). "So we get customers that say, ‘Listen, I get enough data. The last thing I want is more data.' The flip side of that is that they want more data. They need higher productivity; they need more uptime. To get that, they need sensored data."
Many industries are looking to enable more predictive rather than reactive manufacturing, which requires the necessary data from a variety of sensors throughout a plant. Dealing with this dichotomy involves not only better ways to assimilate all the data, but also ways to give users the data they need without overloading them. "To get more equipment health monitoring or predictive maintenance, they want snippets of data," Hanson says. "They want actionable data."
Wireless sensors are a natural fit for actionable data because they can be easily retrofitted into an existing wired infrastructure to get just the data manufacturers are looking for. "A plant might already have wired sensors, but it may not have sensors that are located at the bearing or at the compressor pump or wherever they want to do predictive maintenance," Hanson says. "It can be cost-prohibitive to run wires to get that data."
In some environments, wired sensors just aren't practical, and yet there's a growing need for data points there as well. Waukesha Machine & Tool (www.wmtcinc.com) in Waukesha, Wis., makes workholding assemblies for CNC applications, where constantly moving pallets jogging against each other is too great a demand for wired systems. "Our customers require a wireless pressure monitoring system because of the multiple pallets they run in one machine at any given time," says Kyle Spuhler, designer for Waukesha Machine & Tool.
With wired systems, they just couldn't monitor this application, notes Jim Stawitzky, manager of application engineering for Electrochem Solutions (www.electrochemsolutions.com), which provides the wireless CNC solution for Waukesha, as well as other applications. "If something's in motion, wire is going to fail," he says.
But wireless sensors have even enabled lights-out manufacturing for CNC machining. "If the sensor detects a pressure loss during manufacturing, it will put the machine into an emergency stop and shuttle that fixture out of the machine and bring another fixture/part in for manufacturing," Spuhler explains. "It is also set up to determine if a fixture has a pressure loss before manufacturing, and if so, it will skip that part for manufacturing and move to the next."
One area where wireless sensors still can make strides, Stawitzky says, is in battery life. However, it typically has not been a hurdle, with battery replacement cycled in with scheduled maintenance.
And the fact that they have limited battery power available means that wireless sensors are an inherently good fit for gathering samples of data between resting periods. "If they're only wanting snippets of information or packets of data at a preconceived interval, this is what it does," Hanson says.
"Really, customers only need data when things are changing or in process," Stawitzky adds. "On a 127-pallet system, you can get less than 1% of the data if you look at just the pallet that's being machined."
For a machine builder, wireless sensors can enable the kind of flexibility that many customers need today. "For an equipment supplier, the challenge is where do I put that sensor to pull the data the customer may want," Hanson says. "They'll do their wiring and I/O layout on the machine, get approval from the customer, but once they deliver and go to commission, something's always wrong."
A wireless sensor can be dropped in quickly and easily. "They simply take the data from that device, tie it in to the overall controller if they want or even as a standalone," Hanson explains.
2011-12-27 16:29 阅读(1094) 评论(3) 收藏 好文推荐