Controller memory usage for logging

Controller memory usage for logging


How to calculate total memory required for controller to store logging information for the required duration.

Product Line

EcoStruxure Building Operation, Andover Continuum


NetController (CX9900, CX9940, CX9680, bCX9640)

InfinetController (i2xxx)

BACnet Controller (bCX4040, bCX9640, b3xxx)


Need to know how much memory is needed per point to determine the maximum number of entries and minimum interval time that the controller can use.


The general equation of calculating memory use for controller logging is as below;
* Memory usage per point = { 8bytes + (4bytes * NumberOfLog) }
In addition to that, each controller requires minimum 1~2KB of freemem after the controller logging memory allocated. 

Regarding the log interval, if the point is being logged for controller only, you can set the interval in seconds unit.   But if you configure the point for ExtendedLog as well, the logging interval should be in minute unit.

Again, if there many objects with one minute interval for Extended Logging, it will affect the performance of the Cyberstation and also increases the size of ContinuumDB dramatically in short period of time.

In this case, consider increasing the log interval to 5 ~ 15 minutes for Extended Logging.

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