Omron E5EK PROGRAMMABLE TYPE User Manual page 146

CHAPTER 6 USING THE COMMUNICATIONS FUNCTION
F RS-485
Host computer
RS-485
-
+
FG
J Setting the com-
munications
specifications
F Communications
parameters
Unit No.
Baud rate
Bit length
Parity
Stop bit
6--4
• 1:1 or 1:N connections are allowed. In a 1:N connection, up to 32 con-
trollers including the host computer can be connected.
• The total cable length should not exceed 500 meters.
• Use shielded twisted-pair cables (AWG28 or more) for the cables.
• Attach terminators to the controllers at both ends of the series of con-
trollers connected in an open configuration. For example, in the fol-
lowing configuration, connect the terminator to unit No.30, and do
not connect terminators to unit Nos.0 to 29.
• Use terminators having a resistance of 120 Ω (1/2 W). The total resis-
tance of both ends should be at least 54 Ω.
Shielded cable
Match the communications specifications of the host computer and
E5EK-T controller. When two or more controllers are connected to the
host computer, make sure that the communications specifications of all
controllers are the same.
This section describes how to set the communications specifications for
the E5EK-T controller. For details on the host computer, see the rele-
vant manual supplied with the host computer.
Set the communications specifications of the E5EK-T in the controller's
communications parameters. The communications parameters are set
on the front panel of the E5EK-T controller.
The following table shows the communications parameters (option
mode) provided on the E5EK-T controller and their respective settings.
Parameter/Symbol
A < B : "1" Mark
A > B : "0" Space
E5EK-T (No.0)
RS-485
No.
22 A
21 B
19 A
20 B
Setting
0 to 99
1.2/2.4/4.8/9.6/19.2 (kbps)
7/8 (bit)
None/even/odd
1/2
Terminator
(120Ω 1/2W)
E5EK-T (No.30)
RS-485
No.
22 A
B
21
19 A
B
20
Set Value
0 to 99
1.2/2.4/4.8/ 9.6 /19.2
7 /8
/ e?en /
1/ 2
Inverted items are factory settings.