Ulvac UTM300B, Instruction Manual

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52
SECTION 6 OPERATION
(2) Cables used
RS-485 is a differential transmission and use twisted-pair cables in combinations as shown
in Fig. 6-3.
(3) Connecting the terminator resistor (Terminator)
This product has a terminate resistor (120
Ω
) inside the controller, and the setting of
terminator can be switched ON and OFF. The default setting of terminator is ON.
Terminators are not necessary for multidropped turbo molecular pump with another pump
or pump to which the computer connects is connected to both ends (pump 1 through N-1
in Fig. 6-3).
However, connection of the terminator may prevent communications with certain cable
lengths and RS-485 device types. Connect the terminator to determine whether it is
required.
(4) Cable length
Connection cables can be extended up to 1.2 kilometers, but may be subjects to errors
depending on actual operational environment.
Serial interface protocol is compliant RS-485.
Although we have tested in our environment, all communication with apparatus is not
guaranteed.
NOTICE