Ulvac UTM2300 Series, Instruction Manual

Page: 70 / 102

SECTION 6 OPERATION
56
6
6.8.2.3 CABLE
(1) Cable connection
Fig.6-6 Example of RS-485 Cable Wiring Connections
(2) Cables used
RS-485 is a differential transmission and use twisted-pair cables in combinations as shown
in Fig. 6-6. The shield of the cable should be connected to case.
(3) Connecting the terminator
A terminator (120 Ω, 1/4 W min.) is required for connection.
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. 6-6).
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.
A(+)
B(-)
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
T u r b o M o l e c u l a r
P u m p N o . 1
120Ω
COMPUTER
A
B
B
A
A
B
B
A
A
B
B
A
T u r b o M o l e c u l a r
P u m p N o . 2
Turbo Molecular
Pump No.n
120Ω