Trending a Memory Float

[thepanelshop1]

I currently have a V570 installed at a site that is logging trend data.  Currently it is logging five curves, but my customer has requested a sixth value he would like to trend.  This is a pumping application with a flow meter, and he would like to trend total flow through a pipe.  The problem is that it is a large pump, and therefore a very large value (in gallons).  The controller displays this value on one of the HMI screens.  It is large enough that I had to assign it on an MF.  The curve properties of the trend feature only allows me to choose an MI as a data operand. 

 

Is there a way to do this with an MF?

 

Thank you.

[Michael_P]

Hi Sir, 

We do not have the ability to display the value in the format of a memory float, You are required to link the curve to a memory integer. If the value gets extremely large you can always use the Formula function to include your own formula to shrink the value (for example divide by 10, This way you can use the original (real) value and the graph will display (gallons x 10) just as you tachometer in the car will display(RPM X 1000)

[Flex727]

If the value is large, shouldn't you be using ML instead of MF?

[Michael_P]

Good point Flex727, It is common to manipulate the value if there is a decimal representation. The ML and DW will allow for extremely large values, this in turn can allow you to scale the information with a formula, and include a decimal. The trend however is required to be an MI register. So you can scale the value with the same concept as a tachometer for trending. You will however not get the detailed resolution that you would if a ML could be used in a trend as you are limited to a MI.