APPLICABLE PRODUCTS
- Ewon Flexy
ISSUE / QUESTION / SYMPTOM
- How much data can a Flexy log before it runs out of space?
- Is it possible to change this limit?
- What happens when a Flexy runs out of space?
- How long will it take to run out of space?
POSSIBLE CAUSES / ANSWER
How much data can a Flexy log before it runs out of space?
By default, a Flexy can log 300,000 data points. This is at its default recording size of 6MB, which can be changed to 14MB or 19MB by reducing the space available in the /usr folder. See this table for all possible storage sizes:
| Recording size | Maximum logged data points |
| 6MB (Default) | 300,000 |
| 14MB | 700,000 |
| 19MB | 1,000,000 |
Is it possible to change this limit?
As mentioned in the last answer, the Flexy's recording size can be adjusted from the default of 6MB to 14MB or 19MB. This setting is available in the Ewon's web interface in Setup -> System -> Storage -> Memory Settings. The device always has 35MB of storage available split between the /usr folder and space for recording logs, so the larger the recording size, the less space available for /usr. This generally should not be a concern unless the Flexy is hosting something like a large viewON project.
Fig 1. Memory Settings page on the Ewon Flexy, available in Setup -> System -> Storage -> Memory Settings
Changing the Flexy's recording size will format the Ewon, which means all user settings, tags, programs, and contents of /usr will be erased. Communications settings like IP address and Talk2M registration will remain.
What happens when a Flexy runs out of space?
When the space available for recording historical logs is used up, the Flexy begins overwriting the oldest data first as new data continues coming in (FIFO).
The event log "File was circularized" can be seen in case the historical logging is read by a process (EBD, Datamailbox,...) and the Flexy is overwriting the oldest records at the same time. In this case, the data export is simply stopped.
How long will it take to run out of space?
The amount of time it will take before the historical logging reaches capacity and has to circularize can be determined with this equation:
(DataPointsAvailable / NumberOfTags) * LoggingInterval = Time
- DataPointsAvailable is the number of data points that can be recorded for a given recording size
- NumberOfTags is the number of tags with historical logging enabled
- LoggingInterval is the tags' logging interval in seconds
- Time is the time before circularization in seconds
For example, a Flexy with 5 tags, each logged once every 30 seconds, at the default recording size:
(300,000 / 5) * 30 = 1,800,000 seconds, or 20.83 days of logging capacity.
In the case of tags set up to log based on a deadband rather than a specific interval, LoggingInterval should be set to the tags' polling interval to account for the possibility of the tags leaving the deadband with every update.