Terry is right. As long as you have the two CP's look at the "HOUR" parameter independently, you will be stuck with a max 2 second difference. Have only one CP (can be a third CP)look at the "HOUR" and set some bit accordingly and let both ACCUMs look at that bit instead and you're in business. Regards, René Bakker - EMEATAC - Invensys Systems - Baarn - the Netherlands Subject: Re: [foxboro] Accum Block Reset Date: Mon, 16 Feb 2009 12:09:36 -0500 From: tdoucet@xxxxxxxxxxxxxxxxxx To: foxboro@xxxxxxxxxxxxx Brian, The Master Timekeeper is supposed to keep the internal clocks of all stations (including CP's) within +-1 second, previous to V8. So your two CP's (worst case) could be almost 2 seconds difference. This is the best resolution you should expect to see. If that is acceptable, then you can try the period phase items, below. But remember that you need a 1/2 second or at worst 1 second period. Check to see if you have OM_Scanner overruns on both CP's Terry Doucet, Eng. * Confidentiality Notice: This e-mail and any associated files are intended solely for the individual or entity to whom they are addressed. Please do not copy it or use it for any purposes, or disclose its contents to any other person. Further, this e-mail and any associated files may be confidential and further may be legally privileged. This email is from the Invensys Process Systems business unit of Invensys plc which is a company registered in England and Wales with its registered office at Portland House, Bressenden Place, London, SW1E 5BF (Registered number 166023). For a list of European legal entities within the Invensys Process Systems business group, please click here http://www.invensys.com/legal/default.asp?top_nav_id=77&nav_id=80&prev_id=77. If you have received this e-mail in error, you are on notice of its status. Please notify us immediately by reply e-mail and then delete this message from your system. Thank you for your co-operation. You may contact our Helpdesk on +44 (0)20 7821 3859 / 2105 or email inet.hqhelpdesk@xxxxxxxxxxxxx This e-mail and any attachments thereto may be subject to the terms of any agreements between Invensys (and/or its subsidiaries and affiliates) and the recipient (and/or its subsidiaries and affiliates). _______________________________________________________________________ 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