ICS ELECTRONICS 4809A, Instruction Manual

Page: 43 / 131

2-22
2
4899A or 4809A
DB-25P
20
2
14
3
16
7
3 K
Vcc
220
1K
SD(A)
SD(B)
RD(A)
RD(B)
Tx/Rx-
Tx/Rx+
Figure 2-13 4899A/4809A Pullup/Pulldown Resistor Connections
Figure 2-14 shows an example of a single 4899A or 4809A driving two
Modbus devices over a RS-485 network. In Figure 2-12, the termination
network uses 5 Vdc and ground provided by the Watlow F4 Temperature
Controllers.
1
2
14
3
16
.
7
.
.
25
4899A
or
4809A
WATLOW F4
1
.
11
12
13
14
15
16
WATLOW F4
T+/R+
T-/R-
1K
1K
120
1
.
11
12
13
14
15
16
Figure 2-14 RS-485 Network connections to
Watlow F4 Controllers
Figure 2-15 shows an example of a single 4899A or 4809A driving a Watlow
EZ Zone Controller with a simple point-to-point RS-485 network. The
EZ Zone controller does not have easy terminals to attach a termination
network so the network connections shown in Figure 11 are reused here.