graph help

[brisutterfield]

I am using a RSLinx hot topic in Excel to display a conveyors speed in feet per minute. Typicaly is is around 540 fpm. Lets say that is in cell A1. Also I have another RSLinx hot topic in cell A2 that displays the time that is set in the PLC. Actualy, just the seconds. Status bit S23. So its value will be anywhere from 1 to 60 and update every second. I want to create a line graph in excel that will plot out the conveyor speed. When the conveyor starts the line should start to raise. Starting out from 0 fpm and eventualy climb to +-540 fpm. and the line should also plot the last 30 seconds at all times. Is anyone goodwith graphs that could help me?

[Chris Elston]

Well...I don't work for this company, but I've used their stuff before. It sounds like you need some kind of a historical trending. I could probablly write something in VBA, but maybe this place is worth a look to you: http://www.opcware.com/opc_excel.html I imagine if you want to write this on your own, you'll need to copy data and shuffle them down the rows and excel chart wizard will display the updated graph when you move data using VBA in the macro editor. I've never done this myself, but sounds like a fun Excel / VBA project. What I am trying to say is say you read a value and store it into cell A1. The next time you read the same value, you move the value in A1 down to A2 and put the new value in A1. On the next cycle, you move the data in A2 to A3, and A1 to A2 and the new value into A1. Now with that pattern going, you can just use a normal chart wizard line graphic from A1 to A30 let's say, then everytime you shuffle data, your chart will update in excel in real time.

[brisutterfield]

What you described is exactly right. But I'm not very good at Writing VBA. I'll research the link you provided and see what I can come up with. I could also insert a RS TrendX object in my Excel sheet. This should graph or plot the conveyor speed for me also. I cant get it to work though.