2-14
2
at each end of the cable. Figure 2-11b shows how to use the 8099’s internal
termination network by adding two jumpers to the basic RS-485 connection.
Figure 2-12 shows an example of a single 8099 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. Set the bias
voltages to approximately 2 Vdc and 2.5 Vdc. Use resistors with an approxi-
mate value of 500 ohms/volt.
1
2
14
3
16
.
7
.
.
25
8099
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 2-12 8099 RS-485 Network connections to a pair of
Watlow F4 Controllers
