Asset Management

Easy asset management

There's no need to spend a lot more, just take advantage of the infrastructure already in place

By Ian Verhappen, P.Eng

The vast majority of facilities are not making effective use of infrastructure already in place that could be used to make better use of their installed assets, particularly with respect to their field devices. This is unfortunate because, it's possible to do so with minimal capital expenditure.

As we know, most installations don't effectively use the intelligence in field devices. Most only use HART communications for device maintenance via a handheld communicator. If you're lucky, it gets connected to a laptop or other computer in the maintenance shop to upload/download changes made as a result of a work order—done simply to record work as it's being completed, rather than manually entering it into the scheduling tool. The result is a lost gold mine of data that could easily be captured and used.

Despite the belief that the most important change from HART 7 was adding wireless, I believe the ability to report by exception—making it possible to "wake up" the transmission capability of the transmitter upon change of reading—is the feature that can have the biggest impact on how we use our intelligent field devices. The intent of the "report by exception" feature is to link it to a change in the primary process value. However, if you use this same capability, and link it instead to a configured "common trouble" diagnostics notification sent with associated alert code, this same quality can be used with wired systems to push diagnostic data rather than requiring that it be polled from the host system.

Research done by Shell at facilities in Nanhai, and reported at the 2009 Fieldbus General Assembly, documents how using push (Foundation fieldbus) rather than pull (HART 5) data makes a significant improvement in overall system availability. Most host systems now have HART modems with their analog I/O cards and, assuming they support HART 7, should be able to be set up to accept this information with minimal configuration changes to the point tag to direct it to the appropriate alert tag, thus forgoing the requirement of a separate asset management system.

The NAMUR NE43 standard is effectively a common trouble alarm, so any device that has this capability should be able to be configured to send an alert code to the host system.

If your host system doesn't have a way to make use of the resulting alert tag to drill down to the details causing the alarm, FDT brings a rich graphical environment to assist with maintenance and troubleshooting activities. Many host systems incorporate FDT as part of their system tools. If not, it's possible to download the software to a dedicated device, perhaps in the instrument shop, so the technicians can drill down into the alerting device to determine the cause of the problem, and in many cases, make the necessary change to the device without having to go into the field.

At a minimum, an FDT-based, low-cost maintenance system will be able to help identify the equipment required to fix the problem, so the necessary tools and parts can be ordered and available before going into the field. This alone provides savings, since almost all of us who have worked in the field have spent more hours than we wanted running back and forth to the warehouse. (This is one reason that most folks have a secret stash of often-used parts in their shop cupboard, resulting in excess capital being held in undocumented inventory.)

I realize that not every installed system supports HART 7 and the majority of installed field devices are HART 5, but if you start using this feature with new devices, especially final control elements, the benefits will make it easier to justify a full-fledged implementation and even greater returns. Getting started need not be as cumbersome as it appears, and with a few minor tweaks to how you do business today, you, too, could easily be benefiting from the intelligence in your intelligent devices.