Set the measuring device SECUTEST PSI, not SECUTEST SII or SIII.
Set the measuring device SECUTEST PSI, not SECUTEST SII or SIII. Then read Read device memory. If this does not work, check whether the SECUTEST SI + is correctly entered in the Windows Device Manager: If there is no SECUTEST SI + under Ports (COM & LPT), install the driver Driver contrrol, which you can download here:
http://www.gossenmetrawatt.com/deutsch/produkte/drivercontrol.htm