### Trends and controller memory NOTE If the function blocks in a controller support new-style trends, Exec 3-style trends generally are not needed. If the controller is configured to display new-style trends, Exec 3-style trends will not be displayed. (The displayed trend type is set on the Parameters tab of the driver’s Properties page.) You must consider the types of points you are trending to ensure adequate memory if you do not use standard or extended trends. Analog points require more memory to store the same number of samples as digital points. Non-linear points, such as thermistors, require twice as much memory as linear points, such as 4 to 20 mA sensors. If you disable a trend to free memory so you can trend a different type of point in an Exec 4 controller (for example, an analog point instead of a digital point) you must restart the controller to reallocate memory for the trends. NOTE When you restart Exec 3 and 4 controllers, you lose existing trend information in the controller’s memory. Also, any equipment controlled by the controller will restart. If you change the type of point in an Exec 6 controller, trended memory is automatically reallocated without restarting the controller. Trends are cleared from an Exec 6 controller’s memory when you transfer memory to the controller or change the value in the Interval field. See Trends for Exec 4 and 6 controllers.