YOKOGAWA F3RS22-0N, Руководство пользователя

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4-18
IM 34M6H21-01E 2nd Edition : Aug, 2001-00
4.6 Multi-point Connection
Besides point-to-point (1:1) connections, multi-point (n : n) connections are also
supported in F3RS41-0N.
„
External Connection
F3RS41-0N conforms to the RS-422-A and RS-485 standards. The number of possible
connections for the respective specifications are as shown in Table 4.9.
Table 4.9 Number of Connections Allowed
1: n n: n
RS-422-A 1 : 10
RS-485 1 : 32 32 : 32
Two types of external connection mode are supported, namely, 4-wire and 2-wire.
The 4-wire connection is 1: n where there are n substations for 1 master station.
The 2-wire connection is n : n which includes 1 : n.
Figure 4.3 shows the respective connection examples.
For the 4-wire connection, the send/receive signal wires from the master station to the
substations have to be crossed.
For the 2-wire connection, send/receive signals of similar polarities are connected in the
terminal block in this module. Only 2 wires are laid externally.
*1: Connect the shielded cables to both ends of the ground terminals of FG or SHIELD terminals.
*2: For more information on terminating resistors, see Section 4.6, “
„
Setting Terminating Resistors”
*3: For conforming equipment incorporating the F3RS41-0N to CE Marking, use shielded cables.
For more information, see Section 3.2, “External Wiring”.
Figure 4.3 Multipoint Interconnections
(SHIELD)
SD A
SD B
RD A
RD B
(Substation 1)
Remote equipment
Four-wire multipoints
(Master station)
RS42-0N/
F3RS41-ON port terminal
A
SD
SD
B
RD A
RD B
A
SD
SD
B
RD A
RD B
S G
F G
S G
F G
S G
F G
SD A
SD B
RD A
RD B
S G
*1 FG
*2
*2
(SD A)
(SD B)
(RD A)
(RD B)
(SG)
*2
*2
(SHIELD)
A
B
A
B
(A)
(B)
(SG)
A
B
S G
F G
S G
F G
S G
F G
SD A
SD B
RD A
RD B
S G
*1 FG
*2
(A)
(B)
(SG)
*2
(A)
(B)
(SG)
(SD A)
(SD B)
(RD A)
(RD B)
(SG)
(SD A)
(SD B)
(RD A)
(RD B)
(SG)
(Substation 2)
Remote equipment
(Substation n)
Remote equipment
(Station 2)
Remote equipment
(Station 3)
Remote equipment
(Station n)
Remote equipment
Two-wire multipoints
(Station 1)
RS42-0N/
F3RS41-0N port terminal