Vision 8.1.27
I am trying to understand the update rates and how they are affected by tag groups. All of my history enabled tags were set to a sample mode of “Tag Group”, so I believe that they were polling and entering into the database at the specified time in the tag group. Now, all of the history enabled tags have been changed to a sample mode of On Change, with min and max times that are different from the tag group. My understanding is that the tag will be polled from the PLC at the rate specified in the tag group, then written to the database at the interval specified as the MAX time between samples, unless the value changes in which case the tag is written to the database when it changes. Am I wrong about this? I am trying to prove it out but my database has been stuck in recovery for a while so thought I would ask. Thank you in advance!
The max value is a count of how many tag executions to skip logging if the value has not changed. The max time would be determined by the max value times the tag group polling rate.