So Alex, are you saying that the PID algorithm timing should still be correct since it's off some sort of scanning scheduler based on the clock? Regards Adam -----Original Message----- From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx <mailto:foxboro-bounce@xxxxxxxxxxxxx> ] On Behalf Of Johnson, Alex P (IPS) Sent: Monday, 12 September 2005 4:31 AM To: foxboro@xxxxxxxxxxxxx Subject: Re: [foxboro] Timing changes on loaded CP40 The blocks don't actually use elapsed time for their calculations, they use a BPC counter. For that reason, you see the observed behavior on things like ACCUM block and CALC block in heavily loaded Control Stations. Regards, Alex Johnson Invensys Systems, Inc. 10707 Haddington Houston, TX 77063 +1 713 722 2859 (voice) +1 713 932 0222 (fax) +1 713 722 2700 (switchboard) alex.johnson@xxxxxxxxxxxxxxxx I hope to see you at the Invensys Process System User Group meeting October 3-6 in Houston, TX - www.invensys.com/usergroup2005 <outbind://4/www.invensys.com/usergroup2005> -----Original Message----- From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx <mailto:foxboro-bounce@xxxxxxxxxxxxx> ] On Behalf Of Adam.Pemberton@xxxxxxxxxxxx Sent: Thursday, September 08, 2005 4:54 PM To: foxboro@xxxxxxxxxxxxx Subject: [foxboro] Timing changes on loaded CP40 I have recently discovered that the timer for the OSP instruction of a LOGIC block that is configured to run at 60 seconds continuously is running at around 72 seconds. The relevant instructions are: CST IN ~BO02 OSP 60 OUT BO02 which is meant to generate a low pulse for one scan very 60 seconds. The CP is heavily loaded (~1.5 overruns/sec, 973328 total memory free) but I would not expect it to affect times. Of course it probably also means the PID integral gains for the CP are also being affected (admittedly only by around 17%). Is this normal behaviour for a heavily loaded CP40? Regards Adam Pemberton Coordinator Process Control Lihir Management Company Adam Pemberton Coordinator Process Control Lihir Management Company Ph: +675 9865 655 Fax: +675 9865 666 Mob: Nogat Postal: Australia: GPO Box 905, Brisbane, QLD 4001 PNG: PO Box 789, Port Moresby, NCD -------------------------------------------------------------------------------------------------------------------- This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the originator of the message. This footer also confirms that this email message has been scanned for the presence of computer viruses. Any views expressed in this message are those of the individual sender, except where the sender specifies and with authority, states them to be the views of LMC. -------------------------------------------------------------------------------------------------------------------- _______________________________________________________________________ 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