Hello everyone,

I am working with aSiemens HMI MTP700 Unified, which uses a2GB SD cardfor storage. Recently, I have been receiving the following alarms on the screen:

• Low hard disk space. Tag: SD-X51
• Very low hard disk space. Tag: SD-X

The SD card storesSQLite files, and I suspect that these files may be taking up too much space, causing the memory to fill up quickly.

My questions are:

1. Is it normal for SQLite files to take up a lot of space on this type of HMI?
2. Is there any way to optimize storage or configure the HMI to better manage the available space?
3. Can the storage capacity be expanded without affecting system performance?

I would really appreciate any recommendations or experiences you can share on handling these storage and certificate issues on this HMI.

Thanks in advance!

Hola Sebastián! 

I answer your post with the following:

1. SQLite files can potentially take up a significant amount of space depending on the amount of data being logged and the frequency of logging. This can be particularly true if the HMI is configured to log a high number of events or data points frequently.

2. There are several ways to optimize storage and manage available space on the HMI:

   • Use External Memory Cards:To prolong the service life of your HMI device and manage storage better, it is recommended to use external memory cards, such as a SIMATIC SD memory card ≥ 32 GB, for storing and logging data (SIMATIC HMI HMI devices Unified Comfort Panels PRO: Memory concept).
   • Monitoring and Adjusting Logging Frequency:If logs do not need to be stored permanently, you can disable the retentivity of the alarm buffer and adjust the frequency of logging to reduce the amount of data being stored.
   • Avoid Cyclic Write Access to Internal Memory:Configure your system to avoid cyclic write access to internal memory as it reduces the service life of the HMI device.

3. The storage capacity can be expanded by using higher capacity SD memory cards. It is recommended to use a SIMATIC SD memory card ≥ 32 GB for better data consistency and reliability. However, ensure that the memory card used is compatible with the HMI device and formatted correctly as per Siemens guidelines (FAQ: Why must you not format a SIMATIC HMI Memory Card and what should you watch out for when using standard memory cards?).