Is the IR/serial cable attached firmly to the meter?
Note: For the Fluke 89-IV DMMs and 53/54-II thermometers, best results are obtained when the head of the IR cable is about 1″ away from the meter’s IR port. With the cable that ships with the FlukeView Forms model FVF-SC1, communications problems due to IR reflection can occur if the cable’s IR transmitter is too close to the meter’s IR port.