STP-iXR1606 Turbomolecular Pump
MT-79E-001-D
Page 78
5
SERIAL COMMUNICATION PROTOCOL
DO NOT insert or remove a communication cable while a communication device and a STP
pump are turned ON the power.
Communication interface circuit may break down if surge voltage caused by such as potential
difference of communication interfaces or static electricity is applied to communication line.
Communication failure occurs frequently by broken communication interface circuit.
RS485 is available with communication interface circuit according to the environment, but it gets
failure easily. Check the waveform of the differential signal is normal with measuring instruments,
such as an oscilloscope.
D+
D-
D+
D-
a) Normal b) Abnormal
(abnormal voltage amplitude)
Figure 41 - Example of differential signal waveform