Solution:

User may want to set your driver up for demand polling if: The driver's poll time is slow and you want to get data without having to wait for the next update. You want to poll a device after generating a report. To configure an I/O driver for demand polling Use the AOA I/O Driver Power Tool to set the datablock's access time to a value greater than the scan rate of the display. To poll one datablock on a single device 1. With the Power Tool, enter a primary poll time that is greater than the time it takes for the data to be returned. 2. Set the secondary poll time to DISABLED. This setting prevents the driver from polling when it is not being referenced. To poll more than one datablock on a single device Use the previous procedure to configure each datablock on the device. If you receive overruns: 1. Increase the access time for the datablocks. 2. Increase the primary poll time for the datablocks. 3. Set a phase time for each datablock. If you cannot create separate operator displays or report programs for each device, disable the primary poll time, access time, and secondary poll time for all datablocks and write a script to demand poll all datablocks.