Tina Norris Fields
tinanfields at torchlake.com
Thu Sep 18 08:12:04 CDT 2003
Hi, I have a client who takes voltage readings along pipelines and cables to monitor their health and performance. The data they get back gives them the station reading (feet), the position (GPS), and a voltage reading. The voltage is a sort of "response" voltage triggered by a sending device, which may be "on" or "off" depending on where in the cycle it is, and cycles may be of many different lengths, but should all be factors of 60 (as in seconcds per minute). The first need they had was to separate the readings into their "on" or "off" state. I worked out a user form to request the length of the cycle and whether the cycle started in "on" mode or in "off" mode. This information allowed me to build a lookup table and grab the readings from the combined column and put them in their appropriate columns. The next need was to chart the readings as curves on the same graph, leaving out the zero readings (interpolating the nulls in the curve). The data can come from many thousands of feet of readings. The charts should show readings for 1,000 feet per chart page. I have figured out how to get the total value of station readings and do a an integer division and a modulus division to determine how many pages of charts I need. Here's the part I haven't worked out: How do I code my VB to step through the station readings until it comes to the correct number for establishing the final reading in the range for the first chart? I keep thinking this should be easy, but I'm not getting it. Say, for example, my readings run from 1200 ft to 3700 ft. Clearly, I will need 3 charts. Okay, starting with the cell reading 1200, I need to step down the column until I find the cell reading 2200 approximately. (I've decided to make my 1,000 feet inclusive - so the last reading on chart 1 will be the first reading on chart 2.) Any ideas? Do I need to dynamically create another vertical lookup table? I would appreciate any thoughts on this. Thanks, Tina