A response time out occurs during communication on the UT320, UT321, UT350, or UT351.

Check whether the LL parameter on the controller is ON. If using RS-485 communication, turn it OFF. If it is already OFF, check the following.
If front panel communication, ON
If rear panel communication, OFF
If it is already OFF, check the following.

1. Front panel communication (serial)
   • Is the light loader properly installed?
   • Is the light loader battery still charged?
   • Are any cables disconnected?
2. Front panel communication (USB)
   • Is the light loader properly installed?
   • Is the USB driver installed?
   • Does the LL100/LL200 COM port setting match the COM port number recognized by the PC?
3. Front panel communciation (RS-485)
   • Is the method of connection correct?
   • Do the settings in the communication condition setting screen fit with those of the controller?
   • Does controller PSL (protocol selection) = 0 (PC link)?
4. Ethernet (for UT351- ×A only)
   • Is the Ethernet correctly attached?
   • Is the IP address set correctly?