i use FMB641 for my project that receive data from Vehicle CAN in 200ms period.when i config FMB641 to internal memory after 3-4 min, data missed.is internal memory full?
in other case when config FMB641 to SD card, speed of receive data from vehicle and send data is slow. please guide me
Hello @shahinmlk4247,
Welcome to Teltonika Community Forum 
FMB641 has 2 MB of internal Flash memory thus if you set the device to report for example every 5 seconds and there was no GSM coverage for some time there is a possibility that internal memory will be full and the old records will be overwritten with the newest records.
On the other hand, data sent by the device depends on the Data Acquisition settings and should not depend on the device’s External memory.
For more information about FMB641, you may refer to this link: FMB641 Configuration - Wiki Knowledge Base | Teltonika GPS
I hope this helps.
Kind regards,
Patrick S.