Alternative approach.
I presume you are using a PLC to derive your running status
Rather than datalogging every minute while you are running, how about just log run events (or down time events)? i.e. timer in the plc keeps track of up time (or downtime) in minutes. When a running or downtime event finishes, the plc sets a boolean tag to true, loads the downtime count into a tag and a transaction group logs the minute count (and a time stamp) into a database.
We have done it this way for downtime tracking on some of our attached plant.
You can then sum minute counts between different dates and times to get downtime in a day, downtime in a month etc, as well as being able to allocate reasons for downtime and some other follow on stuff relatively easily. It becomes an easy matter to build reports, charts etc off this.
Note that we are not using the downtime and OEE module.
Just throwing it out there. Good luck! 