Hi Mohsen,
That is a normal response from the transmitter if the sensor/pipe is empty. The empty pipe detection function is supposed to detect an empty pipe (which would also be an electrode circuit open) condition, report that status message, and force the flow reading to zero.
The conductive process fluid completes the electrode circuit (the part of a magmeter that picks up the induced voltage). Without a sensor/pipe full of a conductive process fluid, the circuit is open and deemed empty if the empty pipe detection is active.
The status message should clear once the sensor/pipe is full of a conductive process fluid.
Additionally, the 8732C is an obsolete transmitter. It has been replaced by the 8732E. The C level revision has been obsolete for over 5 years.
Best Regards,
Mike