For years now, industrial-automation proponents have been advancing the benefits of diagnostic information generated by process instruments, and by other field devices such as valve actuators. Plants that have implemented programs for sending diagnostic data to reliability teams can and do improve performance by avoiding unscheduled outages. For example, a pressure transmitter can warn when it is first showing signs of a failure, or a valve actuator can indicate that it is starting to stick.
Unfortunately, few companies have the infrastructure to use this technique. Why? Plants have hundreds or thousands of field devices capable of reporting their status using HART, but device-level networks carrying their data to a DCS often have no means to transfer the data. Upgrading a DCS to include HART-enabled I/O is a costly undertaking, and adding all the diagnostic data collection and analysis tasks to a DCS calls for lots of processing power. Additionally, connecting new devices to a DCS is a costly undertaking, especially if new conduit and wiring is required.
Digital transformation can be applied to address these issues, specifically through the wider use of wireless device-level networks, such as WirelessHART and ISA100.11a. These networks can send the primary variable, but also secondary variables and diagnostic data, to a host system. Everything the device is capable of communicating can be sent via the wireless protocol.
This is a huge advance, since any HART-enabled device can have a WirelessHART adapter added without any interference to the existing wired loop. The reliability team can have its own network where it collects diagnostic information, and then it can perform analysis to direct predictive maintenance efforts. This eliminates the need to do any additional wiring and often costs much less than going through the DCS to get data, so this approach has become the preferred strategy in many locations.
But it’s only a start. To many, using WirelessHART for this purpose is old news. Can’t newer digital strategies do better? Yes, there is a newer alternative—one most of us use every day: Bluetooth.
Here’s how it works...
Bluetooth technology will drive new digital strategies
A technician walks into the plant and opens an app on a smartphone. A menu attached to a database of Bluetooth-enabled field devices appears. After scrolling to the tag of concern, the phone displays all the critical data, just like a traditional HART communicator, but without any wires.
Is a problem developing? The answer is right there. It works because the field devices have native Bluetooth capability. No networks are necessary because the phone handles the communication.
“That’s great,” some might think, “but we don’t have many Bluetooth-enabled instruments.”
For many plants, this is true as such devices have only been available for a couple of years. But, just as WirelessHART adapters can be added to older instruments, dual-purpose adapters are now available to add either or both protocols. WirelessHART can still support a conventional asset-management platform, while Bluetooth can be used as a critical tool for field operations. Implementation of which avoids the need for any additional wiring and bypasses the DCS, with minimal effort required for system integration.
By Tim Shope, vice president of digital solutions with Endress+Hauser
