Setting up a basic graph (weight ver's time)

[ispyisail]

Hi

I'm trying to set up a basic graph of the weight of a bin over time.

I've read all of the help files and it should be easy (must be something wrong with me)

anyway the weight is 0kg to 2000kg and i would like to log time over a 12 hour period

Here is some screen shots

Sorry about asking basic questions

Note: I have tryed different setting from the ones shown on the screen shots, with not luck

[AzeoTech]

Yup it should be easy. Not sure why you aren't seeing anything. Do you have a history? Click on "WEIGH_BIN" in the workspace, then click on the table tab and see if you have a list of values. If you only have 1, then your history is set to 0 or 1. You need to set that to something big enough to allow you to graph the values. Another possibility is that it appears you have a blank trace. Not sure how you got it, or if you'll be able to delete it, but try just deleting it. Otherwise, go to a blank page, add a new graph, put WEIGH_BIN in as the trace and click ok. The trace might be off scale but you should at least see the date/time advance.

The fact that the date/time doesn't advance tells me that you have no history or that blank trace is throwing it (though I don't know why it would).

[ispyisail]

My graph now works

Sorry about posting for a basic feature.

I'm not sure exactly what the problem was, but I suspect my problem was related to:

1. Graph scaling

2. Freeze / Thaw (needed to thaw graph)

3. Data history (I think the problem was the first 2 options)

Thanks

[AzeoTech]

Well, it wasn't the scaling, but you are right, it could have been frozen before you had any data and then once you had data, it stayed frozen in the generic scaling (the graphs don't scale properly until there is data to plot). To tell if a graph is frozen, simply click on it (no Ctrl key) and look at the box around it. If it is green, then it is thawed and the graph scaling is what is displayed in the properties. If it is purple, then it is frozen and the properties scaling will do nothing.

[ispyisail]

Hi

I thought i had fixed the problem

Its crazy, it works sometimes and not others. For example I had the "Logging" set to 1 second then changed it to 60 seconds but it still was logging at 1 second intervals. "Row" logging works sometimes. A few other strange things happen as well

I suspect my problems could be something to do with OPC server?

[AzeoTech]

Its probably because you have the persist length set to 1. With a timing of 60 the values are only going to be updated once every 60 seconds. With persist length set smaller than history (except persist of 0, which means off), I think persist will override it, so you only see the latest value. It may appear to change less often than once a minute because the value is actually not changing. Try setting Persist to match the history.

[ispyisail]

Thanks

It now appears to work

I sill don't understand "persist" but it works

[AzeoTech]

If you don't know what persist is, set it to 0. In fact, if you don't know what a particular parameter is for, I recommend always leaving it at the default. Many of the built in features have a number of options. We tried to make it so most can be kept in their default settings unless you want to tweak.

History is the number of data points kept in memory to allow for graphing and calculations. Unlike other apps, we let you specify exactly how much memory you want to use for each channel. The problem with history is two-fold: 1) when you restart DAQFactory, the memory and therefore the history is cleared, and 2) the memory in your machine is almost certainly much smaller than your harddrive space.

So, there is Persist, which essentially extends the History to the harddrive. If you are only concerned about keeping the history when you restart, then typically you'll set the Persist to the same as the history. If you want to be able to easily access more data than would otherwise fit into the system memory, then you can make the Persist much, much bigger than the history. You could also read from log files, but Persist is a bit more transparent. To access persist data past the end of the history you must subset your data though.