Edwards SCU-350 Series

SCU-350 Series Control Unit for Turbomolecular Pump
MT-21E-201-E
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SERIAL COMMUNICATION PROTOCOL
DO NOT bundle a communication line with a protective earth conductor or a power line.
Moreover, keep away a communication line from the apparatus used as a noise source as much
as possible.
As radio frequency noise measure, place a ferrite core on both ends of the communication cable.
When electromagnetic interference caused by radio frequency noise in frequency band (150 kHz
to 1 GHz) affects communication, attaching ring ferrite cores to the cable is effective to reduce
communication failure.
Figure 37 - Example of ring ferrite core installation
Avoid installing a power line and a communication line in the same metallic duct.
When unavoidable, separate a line with a metal separator certainly, and connect the duct
containing a metal separator certainly to GND, or installing a communication line put into
conductive pipes, such as metal.
Communication line
Metallic separator
GND
Power line
Metallic duct
Figure 38 - Example of cable installation in metallic duct
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.