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)=20 minus the value 15 minutes ago and set a flag if the difference is greater than=20 a fixed value. (5 sec / sample =3D 180 samples / 15 minutes) *100 What is the best way to read the two values? =20 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=join to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave