Martijn, Thank you for your suggestion. I did think about DTIME but at 10 = buckets per block with 10 seconds period that means 9 DTIME blocks per = (15 minutes) signal or 900 DTIME blocks. I was hoping that a single = C-program reading an ascii file listing all my C:B.P of the signals then = setting a BOOL.VALUE (if TRUE) would be much easier to maintain. The = values are already inside the Historian. We also looked at using IND blocks to move the measurements through a = matrix every 10 seconds for 15 minutes. On a test bed, this worked fine = but for the 100 signals, the memory required in the CP is too high to = make this practical. I appreciate your response and it may be the way to go in the end but it = makes the maintenance of this application a little difficult if a = specification change (eg. 20 minutes instead of 15 minutes) is required = later. Terry -----Message d'origine----- De : foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx] = De la part de m.d. Envoy=E9 : September 28, 2007 2:55 AM =C0 : foxboro@xxxxxxxxxxxxx Objet : Re: [foxboro] AIM Historian Terry, I would solve this in control.=20 Using a DTIME block to do the 15 min delay and an AIN or REALM block to = do the alarming. The loops can run at regular processing period (0,5 or = 1 sec).=20 Martijn Daamen Senior Application Engineer Invensys Systems N.V./S.A.=20 Kontichsesteenweg 54 2630 Aartselaar - Belgium=20 T: +32 (0)3 205.14.56 =20 F: +32 (0)3 232.17.98 M: +31 (0)6 22267610 martijn.daamen@xxxxxxxxxxxxxxxx www.invensys-systems.be=20 ----- Original Message ---- From: "Doucet, Terrence" <tdoucet@xxxxxxxxxxxxxxxxxx> To: foxboro@xxxxxxxxxxxxx Sent: Thursday, 27 September, 2007 9:41:41 PM Subject: [foxboro] AIM Historian List, We have AIM*Historian gathering thousands of measurements every 5 = seconds. On the same AW70 we would like to write a C program.. For 100 measurements, we want to look at the latest value (either current or last written to = Historian)=3D20 minus the value 15 minutes ago and set a flag if the = difference is greater than=3D20 a fixed value. (5 sec / sample =3D3D = 180 samples / 15 minutes) *100 What is the best way to read the two values? =3D20 We would like the = caulculations to be performed about every 10 seconds. Does anyone have experience with similar applications using AIMAPI or = AIM*DataLink? Thanks, Terry _______________________________________________________________________ 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=3Djoin to unsubscribe: = mailto:foxboro-request@xxxxxxxxxxxxx?subject=3Dleave ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try = it now. http://uk.answers.yahoo.com/=20 =20 =20 _______________________________________________________________________ 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 =20 foxboro mailing list: //www.freelists.org/list/foxboro to subscribe: = mailto:foxboro-request@xxxxxxxxxxxxx?subject=3Djoin to unsubscribe: = mailto:foxboro-request@xxxxxxxxxxxxx?subject=3Dleave =20 _______________________________________________________________________ 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