Making very clear that ISA is committed to working with the HART foundation, Chip Lee, who is in charge of standards at ISA among other things, introduced Wally Pratt, the chief engineer of the HART Communication Foundation. Pratt began by giving a history of the HART foundation, and described what it does, and how it does it. "We are an IEC approved international standard. WirelessHART is an integral part of that standard," Pratt said, correcting something both Wayne Manges and Pat Kinney had said, erroneously, this morning. "WirelessHART is an integral part of HART 7.o, which has just been approved." HART has about 42% market share of all instrumentation. "Since HART became an open standard," Pratt said, "we've sold about half as many devices as all the devices that there are in plants. We aren't going away anytime soon." You can see a really good multimedia version of an earlier incarnation of Wally's talk at http://www.controlglobal.com/articles/2007/184.html WirelessHART is an open, and interoperable standard. It is intended to be as easy as using wired HART. It is intended to enable wireless access to existing HART devices, using the same configuration, amintenance, diagnostic tools and procedures, and minimize the training requirements. Pratt talked about a major use case-- wireless connection to existing HART devices. Many installed DCS systems do NOT have digital HART signal inputs. This can be enabled by a wireless adaptor. We also wanted, he said, to allow for a new class of field devices that are battery, solar or field-powered devices. The HART 7 specifications have been approved by the membership with nearly unanimous ballot. There are new specifications for the physical layer, the data-link layer, network management, wireless commands, wireless devices, enhanced universal commands, 27 new common practice commands, and a WirelessHART User Manual. HART 7 is fully backward compatible with previous versions of HART. This is a multi-company development using standard HART practices. More than 25 companies were involved in the development, including aBB, Dust, Emerson, Honeywell, Siemens, Endress+Hauser, MACTek, Omnex, Pepperl+Fuchs, Yokogawa, and others. WirelessHART is a self organizing and self healing wireless mesh network. It is:
- preserves the HART user experience and command structure.
- robust security using industry stanarrd AES-128 ciphers and keys
- IEEE802.15.4 radio at 2.4 GHz--frequency hopping device.