NeSSI Focus Group
Focus Group Leader: John Mosher, Honeywell
Note Taker: Joe Dragavon, UW Chemistry
Wednesday, November 5, 2003
The focus of the discussion for this meeting was around the Bus Comparison Matrix, as presented by John Mosher. According to Mosher, the file was going to be posted on the web.
It was stated by Mosher that the group wants intrinsically safe bus systems to address the sensor bus portion of the NeSSI Gen 2/3. It was commented by Lloyd Burgess (CPAC) and others that one does not need to invent the bus system, but the group must find the correct resource. It was commented by Mosher that all the buses listed in the comparison are of open architecture and that there probably be a licensing fee for use.
A question from the audience asked that a brief comparison between the buses listed and Devicenet (sp). Mosher responded with that some of the buses were better, some were not. Burgess suggested that the group needs to define the requirements of the nodes and buses, and that this will help limit the amount of comparisons that need to be done. For example, Profibus was designed around large business and large data packets. This may or may not be ideal for NeSSI.
Next, Mosher brought up the NeSSI Sensor Requirements document. This document contained a list of 12 requirements. Each requirement was explained and also had information regarding the reasoning behind the requirement and its impact on NeSSI. It was suggested that this document also be posted on the web.
An audience member asked if the power issue for all the instruments on NeSSI was resolved. The general response was a yes, but each platform will be unique since not all the instruments will be the same from system to system. Mel Koch (CPAC) inquired if the group was asking the bus questions in the right way. Koch went on to suggest that the questions/information be sent to the individuals involved instead of the entire CPAC community.
The group also discussed Sensor Actuator Manager (SAM) controllers. Koch asked “What is SAM?” [SAM = Sensor Actuator Manager] Apparently, there are multiple definitions of what SAMs are and what they do. Koch requested an introduction on the topic of SAMs before all the details. [Refer to Fig. 12 Page 33, Gen. II specification for full description of SAM functionality.] Mosher stated that the SAM system will be the diagnostic system sitting on NeSSI.
Two final questions were asked for the group to think about until the next meeting. The first question was about whether or not the group knows how much data needs to be handled. The second question inquired about how the data was going to be sent (as a continuous data stream, for example).