Walt,
I like your letter sent via Lois to the SP100 list. However, a few clarifications. You may publish this if you want.
From the then and current chairperson of SP50 (me): I know the concept that SP50 failed by producing an 8-headed monster, but it didn't. The monster was produced by the IEC/SC65C/WG6 committee by majority vote. SP50 never voted to adopt that version. The Fieldbus Foundation based their work only on ANSI/ISA-50 parts 2 and 3 (PHY and DLL). Later FF created HSE to substitute for the fast buses specified in 50.02, and by vote of the IEC committee was included as one of the 8 in the monster.
Actually, I am pleased to see the 25 proposals submitted to SP100 reduced to only 2 in such a short time. Even then, these 2 are not so far apart. The Honeywell-led WNSIA proposal does not include mesh networking at the field level only because there is no standard or even a draft standard on which to base it. Mesh is included in ZigBee, but in layer 3 above the part standardized by IEEE802.15.4. The upper level WNSIA network includes mesh networks based on the draft IEEE 802.11s, which is at least in the draft stage. The Emerson/WINSA/Siemens/et.al. group uses the ZigBee form of mesh in the field level.
I believe that these technical issues are easily worked out. I do not detect a desire expressed or implied by any committee member that any current proprietary network technology should be the basis for this standard, such as was stated over and over again by the Profibus advocates during the SP50 and IEC working group members during the fieldbus standards battles. However, your letter is welcome as a constant reminder that competitive advantage has no place at the standards committee table.
Dick Caro
Leaders relevant to this article: