DataLog Display

[scottmurphy]

Hello, I am wanting to display an analogue & digital trend on the same screen. To avoid conflicting scaling issues, the best way is to do 2x graphs, with the scales set accordingly. The issue that this presents, is the scrolling back/fwd through history values. I could add the scroll bars to each chart display, but then the user would have to navigate both at the same time. Not a major problem I guess, but does make it slightly frustrating. Ideally, it would be nice to be able to link the start times, but I am doubting that this is possibly. Any other ideas on a workaround, or is it scroll bars on each?

[ECSI]

What I did recently was combine the analog and digital on one graph. For example if your analog scale was 0 to 1000 the graph scale can be set to 0-1000 on the Y axis. Then, for the digital status 0 or 1, you can use the PLC (or a NS macro) to set a word value to 25 if the bit is off, and 150 if the bit is on. Now use that word as a trending point instead of the digital bit. You should then see your analog point varying with the process, and a square wave at the bottom of the graph representing your digital point status. Hope that made sense. By the way I used 25 for the 0 bit status just to keep the square wave offset from the zero mark on the graph, for clarity purposes.

[scottmurphy]

Yeah, that makes sense, I was hoping to avoid it, but your suggestion about the scale triggered an option. I could make the scale -100 to 500 for example, so if the analogue variable is -10 to 40, I could then make the digital value -90/-80, that should give some clarification. I will do some testing, and see what it looks like.