tag:blogger.com,1999:blog-5457156492515509817.post3235904100890358233..comments2023-10-23T13:54:17.101-04:00Comments on FOUNDATION Technology: Tom Moore of IMS Research Clarifies their Position on Ethernet vs FieldbusLarry OBrienhttp://www.blogger.com/profile/01905029154718867325noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-5457156492515509817.post-48214192123062982782013-08-09T09:00:39.804-04:002013-08-09T09:00:39.804-04:00The real groundswell out there is not from fieldbu...The real groundswell out there is not from fieldbus to Ethernet, but from hardwired analog 4-20 mA and discrete on/off signals to digital communication networks. If it will be fieldbus or Ethernet is secondary. In my personal opinion, Ethernet is great for the control network at level 2 of the Purdue reference model, as well as the MES and ERP levels above. Ethernet is also taking hold for drives, motor starters, MCC, wireless gateways, and small package unit PLC at level 1-1/2 of the Purdue model – eating into the “H2” level of fieldbus. I guess for this reason the Fieldbus Foundation dropped the development of H2 and went straight for Ethernet: HSE at this intermediate level. As far as sensors/transmitters and positioners/actuators/valves at level 1 of the Purdue model these mainly use hardwired analog 4-20 mA and discrete on/off signals. We need digital communication down to the sensors and actuators too. I see a little bit of Ethernet used in magnetic and Coriolis flow meters as well as electric actuator / Motor Operated Valve (MOV). However, Ethernet is struggling to take the place of 4-20 mA and on/off signals. For digital communication with intelligent pressure, temperature, level, and interface level transmitters, vortex flow meters, as well as pH , conductivity , and amperometric analyzers as well as control valve positioners, and intelligent on/off valves at level 1 of the Purdue model I do not see any Ethernet. Instead, at this lower level, plants should use one of the “H1” level fieldbus protocols to provide digital communication all the way including the “first meter”. Important characteristics of “H1” fieldbus include long distance, passive field junction boxes not requiring power supply, two-wire bus power, intrinsic safety, and robust connections etc. Indeed fieldbus and Ethernet complement each other to eliminate hardwired 4-20 mA and on/off signals.Anonymousnoreply@blogger.com