Macintosh bootable volumes are supported on the internal 2-port PCI card (part number TSATA) but are not supported on any of the other SATA cards at this time.
This condition occurs when the System Preferences Energy Saver Put the hard disk(s) to sleep when possible checkbox is checked (on), or the Disk Sleep Timer is enabled; the Tempo-X SATA card using firmware version 1.2 does not support disk sleep.
To correct this issue, update the Tempo-X card's firmware to version 2.0 or later. Download and run the installer to add disk sleep support.