When sending the CLT message to the board, the board is analyzing the cycle time.  When 1200 cycles are expired the time is measured and than devided by 1200. This value is send to HMI. 

CommandHMIBoardSyntaxRemark
CLTSendReceive@CLTMeasuring cycle time is started on the board.
CLTReceiveSend@CLT,<cycle time>in mS
Possible error messages coming from the board
%FAT-UNKCMD-BTSERIAL, Unknown command received