Installation, Operating & Maintenance Instructions
Series 615 DN 40 (I.D. 1.5”), RS485
VAT Vakuumventile AG, CH-9469 Haag, Switzerland
Tel +41 81 771 61 61 Fax +41 81 771 48 30 [email protected] www.vatvalve.com
289111EB
2013-02-05
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3.12.3 RS485 network topology
Note:
In the picture above, the general network topology of
RS485
is shown.
N nodes
are connected in a multipoint
RS485
network. A termination resistance is necessary on both ends of the line to e
liminate reflections. Use 120Ω resistors (R)
on both ends. The
RS485
network must be designed as one line with multiple drops, not as a star.
3.12.4 Connection cable drawing
Half duplex
Full duplex
R-
R+
T-
T+
120Ω R
11
24
13
12
HOST
R 120 Ω
R+
R-
T+
T-
Valve
Twisted pair
cable
Twisted pair
cable
Wiring:
T+
to
R+
T-
to
R-
R+
to
T+
R-
to
T-
11
Valve
24
12
13
R-
R+
T-
T+
120Ω R
HOST
R 120Ω
T+
T-
R+
R-
Twisted pair
cable
Wiring:
T+
to
T+
T-
to
T-