Ajay, The Foxboro documentation that answers your questions is: Network Cable Systems Installation and Maintenance B0193UW, Rev D Network Cable Systems Planning B0193UX, Rev E I/A Series A2 Nodebus/Control Network Interface(NCNI) PSS 21H-7B5 B4 The maximum fiber optic fieldbus Cable Length is 4 km (point to point). If it were my installation I would lean toward the Fiber Optic Fieldbus based on past problems with nodebus extenders, but the fiber optic capabilities of the NCNI's may provide a good solution. However, Foxboro documentation, (PSS 21H-7B5 B4), has a stated point to point distance limitation of 2km and it sounds like you may be pushing that. There are a few considerations to think about: Can you forsee a need to install nodebus equipment in the remote location in the future? It is always wise to pull additional fibers. You will need 4 fibers if you want a dual nodebus or fieldbus so you would probably install a 6 fiber cable anyway. But compared to the cost of installing 6 fibers, installing 12 isn't much more expensive and it would give you the future capability to have both nodebus and fieldbus communication at the remote location. Tom VandeWater Control Systems Developer/Analyst Dow Corning Corporation Carrollton, KY USA -----Original Message----- From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]On Behalf Of Ajay.Tathgir@xxxxxxx Sent: Saturday, January 31, 2004 1:22 AM To: foxboro@xxxxxxxxxxxxx Subject: [foxboro] Optical Field Bus / NCNI's Hi! All Wanted to know how long can i run a field bus using the optical cable. The issue is that the present system is at location 0, and there is another unit around 1.5 kms away. I was thinking of putting the CP's at location 0 & using a optical field bus to connect to FBI's around 1.5 kms away. The 1.5 could be 2.5 also. Or should i create a extended node and connect the same using NCNI's through a optical link. In the present system i've four 1 X 8 MS, and i'll have to add two 1 X 8 MS at the new location. It would be good to know if there are issues involved with any of the above configurations. The system is 6.1.2 Unix having 51B stations. TIA & Regards Ajay Tathgir Reliance Industries Limited Mumbai - India _______________________________________________________________________ This mailing list is neither sponsored nor endorsed by Invensys Process Systems (formerly The Foxboro Company). Use the info you obtain here at your own risks. Read http://www.thecassandraproject.org/disclaimer.html foxboro mailing list: //www.freelists.org/list/foxboro to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave _______________________________________________________________________ This mailing list is neither sponsored nor endorsed by Invensys Process Systems (formerly The Foxboro Company). Use the info you obtain here at your own risks. Read http://www.thecassandraproject.org/disclaimer.html foxboro mailing list: //www.freelists.org/list/foxboro to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave