About Set Points on graphic

[kanber]

Hi,

I need to help about showing set point on graphic. Please see on attached file. I am logging data every 180 second. But if set is change It seem to be a linear change. But I want it to show as I specified with the blue line. Other programs had such a feature for set points.

[AzeoTech]

Sorry, the file wasn't attached.  But I believe you are talking about trending an output?  That it causes a graph to just draw lines between the points when the set point changes, and not showing the current state of the output? 

If so, first usually it is best to actually use an input to read the status of the item you are controlling.  For example, if you were controlling a pump, you could have an input that reads the current use of the pump so that you know that the pump actually turned on.  This is so you get the proper feedback.

But, understandably, this is often overkill.  To trend a setpoint like you described you need to build a history.  The easiest way to do this is to create a test D toi A channel to store the continuous history, then in the Event of one of your input channels, put:

myGraphOutput = myOutput[0]

so that this test channel (myGraphOutput) gets updated with the current control state of the output channel (myOutput) every iteration of your regular inputs.

[AzeoTech]

You should probably add the same script to the myOutput channel's event.

I've attached an example.  It trends myOutput in black (sloped lines) and myGraphOutput in blue.

outputsample.ctl