Innovations in Sensors such as proximity switches have been impressive. The packages are smallerCONTROL ENGINEERING China版权所有, yet have longer ranges. Microcontroller-driven “teach-in” processes for precise sensor settings have replaced cumbersome and inaccurate potentiometer synchronization. Diagnostics have expanded to include such things as early warnings against dirt contamination.
　　Yet, to be able to fully use these new developments in diagnostic and parameter information, they must be made available to the automati

on system. Beyond the basic on/off switching signalCONTROL ENGINEERING China版权所有, the interface between the I/O module and the sensor should provide the possibility of exchanging diagnostics and parameter data. Only in this way can the capability of the sensors be optimally utilized.
　　Until now控制工程网版权所有, the only way to communicate with “intelligent” proximity sensors is with a separate PC directly connected to them控制工程网版权所有, because this newfound intelligence stops at the interface. It goes no farther because there is no way for it to go. Modern automation systems do not have the benefit of standardized控制工程网版权所有, bidirectional communication between the sensors and the control level.
　　As a result, the sensor’s parameters must be configured directly by hand, either before delivery or during the commissioning phase of a new machine when it is installed.
　　And that’s exactly where the backup of these sensor parameters stays: on the PC that was used to commission them. It is easy to see the problems that will arise from this. If a sensor (or actuator) needs replacing, woe be it to the technician if he can’t find a copy of the parameter file. He’ll have to enter them all over again in the new devices.
　　What about sensor diagnostics? Few technicians want to leave their laptops connected to the sensors during operation, so continuous diagnostics are usually not available. While some sensors do provide a diagnostic output signalCONTROL ENGINEERING China版权所有, this requires a separate I/O line. Most end users understandably don’t want to double the amount of I/O wiring t