I caught up with Emerson’s Dan Daugherty, whom you may recall from earlier digital bus and wireless-related posts. Dan has been focusing his efforts on WirelessHART project implementation practices over the past year. Much like the introduction of various fieldbuses led to the need for design guidelines to better incorporate these technologies into automation projects, the same is true with IEC 62591 WirelessHART technology.
Dan recently presented at an Intergraph SmartPlant Instrumentation (SPI) technical user forum in Houston. SPI is the project management tool of choice to manage the instrumentation required on a project. Dan and members from Emerson’s wireless team have been working with the Intergraph team to collaborate on getting the WirelessHART structures defined for SPI.
One result from this collaboration was a section in a recently published guide, WirelessHART Systems Engineering Guide. Section 12 on page 61 shows how WirelessHART devices can be fully documented in SPI with minimal customization. This section shares an example with associated screen captures of this documentation process.
The goal of any automation project is get the project done on time, bring it in on budget, and look for ways to achieve cost savings where possible. Increasing the number of wireless devices where practical can lower overall installation costs and improve the robustness of the wireless network communications. Beyond improving installation costs, the key is to look for new ways to exploit the wireless technology to improve operational efficiency and profitability. Existing barriers that formerly were too expensive to do with wires-whether due to the need for trenching, or some physical gap or distance in the terrain now becomes possible.
Many new ways to apply wireless devices to improve the process and reduce costs is possible through collaboration between Engineering, Procurement and Construction (EPC) providers, process manufacturers, and the automation supplier. By bringing their unique perspectives together during the front-end engineering design (FEED) process, these opportunities are less likely to be overlooked.
Projects always begin with some kind of list of measurements. Project guidelines such as application types and installation topography help narrow down the list for suitable wireless device candidates. The radio range of these devices can vary if they are located near dense pipe racks versus open fields.
Dan noted that wireless networks are typically scoped around process units, but it is OK to have more than one wireless network in a unit. Next, devices are assigned to wireless gateways, typically according to physical location. Part of the design process is to use a checking tool such as the AMS Wireless SNAP-ON where the number of possible communications paths and distances are checked to verify alternative communications paths are available for each device. The findings from this engineering work are documented.
He showed this project flow using the SPI management tool. Global User Defined Fields (UDFs) define elements such as the wireless gateway with which a device associates, WirelessHART adapter, network design layout, scan rates, etc. Filtered views assist in sorting out device criteria such as sample rates to help decide which devices are wireless candidates.
Other steps in documenting WirelessHART devices in SPI include creating the wireless instrument types, defining the symbols in the loop drawings, showing the gateway power and communications connections, completing the SPI specification sheets, and adding the WirelessHART devices and gateways to the same plan drawings as the wired devices. However, the security information should be documented according to local security policy, not in the SPI construction package. See these steps in action on pages 61-72 in the WirelessHART Systems Engineering Guide.
This collaboration between Intergraph and Emerson engineers as well as the guide is helping to simplify the process of incorporating wireless instrumentation in automation projects.
