Data Recovery Service - Technical Tip for Battery-less Jace's
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- Published: Monday, 17 May 2021 19:22
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The Data Recovery Service (DRS) is required by all battery-less JACEs and should NOT be disabled.
The DRS is designed to save station information in the event of a power failure. While the station is running (but between station save times) a buffer is being filled with the changes that happen in the station.
This buffer includes any changes that happen in the config portion of the station, but also includes all histories and alarms that have collected since the last station save.
The DRS saves changes to the database to SRAM and on a station restart it copies them back into the running station. DRS caches all data deemed ‘critical’ and then when a buffer fills, it forces a station save. This station save happens independently of the scheduled station save. Scheduled station saves should happen no more than ONCE PER HOUR.
Sometimes stations will save way too often, sometimes every few minutes. This is due to the station having lots of control points changing value very fast. By default, most of the points in the station are deemed critical. Any component that does not have the ‘Non Critical’ flag set on the slot is (by default) deemed ‘critical’. So the DRS will cache all of the value changes and once the buffer fills, save the station.
Looking for more details? If you have Ax or N4 installed on your computer, you can refer to the docJaceDataRecovery document in your Niagara release directory docs folder. The path should look something like this C:\Niagara\Niagara-4.4.92.2\docs\docJaceDataRecovery.
Controlco Support has a program object that will go through the station and set all of the slots ‘Non-Critical’ flags so the DRS won’t cache the value. All this means is that on a reboot the point will need to read the value. This allows the user to clear the ‘Non Critical’ flag on anything they feel they need to have the value of when the station restarts.
If you would like a copy of the program file (please specify Ax or N4), please fill out our support form and one of our techs will send you the file.