Thanks Brad. I understand better how the ROC works now BUT...as the "clients of the D.C. Madam" say, here's what I really want is... if that 1.67 Deg/sec rate is sustained for 5 minutes then alarm. Is there an easy way of doing that without bringing that "alarm bit" into a logic block and "DON" for 5 minutes? Regards, Michael L. Jaudon TRONOX, LLC (Technology Group-Hamilton, MS) (662)343-8710 Office (662)304-0313 Cell mike.jaudon@xxxxxxxxxx If you are not the intended recipient of this e-mail message, any use, distribution or copying of the message is prohibited. Please let me know immediately by return e-mail if you have received this message by mistake, then delete the e-mail message. Thank you. -----Original Message----- From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx] On Behalf Of Wilson, Brad Sent: Friday, May 04, 2007 10:08 AM To: foxboro@xxxxxxxxxxxxx Subject: Re: [foxboro] Rate of Change Alarming I just did a test with a RAMP and REALM and it worked as expected. The trick is to get the units correct ... the RAMP.OUT is units/min and the REALM.ROCVAL is units/sec. When I RAMPed at 50 %/min it showed up on the REALM.ROCVAL as 0.833 %/sec. In your case I would try Make your REALM input scaling the same as the AIN that feeds it REALM.ROCLIM =3D3D 1.67 (deg F/sec or 500 deg in 5 min) REALM.ROCTIM =3D3D 5 (mins) REALM.ROCOPT =3D3D 1 (enable ROC alarming) Now, this will alarm if the instantaneous rate ever goes over 1.67 deg/sec. ROC alarming is absolute value, so you'll also get an alarm if it falls 1.67 deg/sec. You might be able to "dampen" the alarming by using a filter in the AIN block, but that is questionable. Brad Wilson brad.wilson@xxxxxxxxxxxxxxxx Invensys Systems, Inc 1090 King Georges Post Rd, Suite 204 Edison, NJ 08837 732-874-0087 -----Original Message----- From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx] On Behalf Of Jaudon, Mike Sent: Friday, May 04, 2007 10:40 AM To: foxboro@xxxxxxxxxxxxx Subject: [foxboro] Rate of Change Alarming List, =3D Can anyone tell me how and what to set on a REALM block to make the ROC work? In the past I have set up on a test bed and used a RAMP block to test but it never works as I think it should. =3D I want an alarm to be generated when the temperature goes up 500 DegF in 5 minutes. The temp normally operates at a constant value but if it increases by the 500 Degrees within 5 minutes then I want an alarm. =3D In the past I have accomplished this by building two AIN blocks and changing the "period" on one and sending these to a REALM block (MEAS & DEVSPT). One problem I have now is there is no period with a 5 minute execution. Besides if I could configure the REALM correctly I would only have to create one block instead of two. =3D Anyone with any ideas? Michael L. Jaudon =3D TRONOX, LLC =3D (Technology Group-Hamilton, MS) =3D (662)343-8710 Office =3D (662)304-0313 Cell =3D mike.jaudon@xxxxxxxxxx =3D If you are not the intended recipient of this e-mail message, any use, distribution or copying of the message is prohibited. Please let me know immediately by return e-mail if you have received this message by mistake, then delete the e-mail message. Thank you. =3D =3D =3D _______________________________________________________________________ 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. 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