New proximity sensor characteristics rated important by respondents were automatic sensitivity adjustment and self-teach feature, ranking fourth and seventh, respectively. |
Longer sensing ranges, more resilient construction materials and techniques,
and better electronics/cabling have all added to the ruggedness of proximity sensors overall. However, these features are often available only in premium units at prices higher than standard. In each case, users need to weigh installed cost against production downtime.
Sensors unplugged
Most users still do not use sensors on a device network. Those who do, however, use standard sensors with interface modules more than twice as often as network-enabled varieties. According to Nazario Biala, proximity sensor product manager at Omron Electronics LLC (www.omron.com), this trend will continue, at least in the short term.
‘A couple of things need to take place before the 2:1 ratio can change,’ says Biala. ‘First, users of industrial automation need to be better educated on the benefits of system and device-level networks. Associations, such as ODVA [Open DeviceNet Vendor Association; www.odva.org], have done a good job of educating the industry of the benefits of implementing device-level networks. However,’ he goes on, ‘a wider scope of industry education needs to take place for wider market acceptance. Additionally, the industry is waiting for the cost of network components, such as photoelectric sensors and proximity sensors, to come down,’ Baila says, adding that those waiting for a winner in the fieldbus wars have been missing benefits of network-enabled devices.
Looking at communication technologies preferred by those who use networked sensors in automation systems revealed