Hello all, We are looking into some strange behavior after a recent upgrade from a CP30 to an FCP270. A PIDA block was set to be Proportional Derivative, MODOPT=3, PBAND = 125, INT=0.075 (INT is BTIME in PD mode). The BCALCI and FBK were both connected to the PIDA's own .OUT parameter. The Period is a 3, Phase is a 2. I think the BPC of the CP30 and FCP270 are both .5 seconds. Behavior In the FCP270, the output drives to the low output limit. It's as though the loop is in open loop control. Looking at trends indicate that this loop was controlling in the CP30. The configuration is identical to what it was in the CP30. Any advice on what to check. Thanks, David ________________________________ Confidentiality Notice: The information contained in this message is private and confidential. This information is intended only for the individual or entity named above. If the reader of this message is not the intended recipient, you are hereby notified that any use, review, dissemination, distribution, copying or action taken based on this message or its attachments, if any, is strictly prohibited. If you are not the intended recipient, please contact the sender by reply email and delete or destroy all copies of this message and any attachments. Thank you. _______________________________________________________________________ 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