Rs-485; Setting The Communications Specifications; Communications Parameters - Omron E5AK User Manual

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
• Up to 32 controllers including a computer can be connected to the
host computer.
• 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 a series of con-
trollers connected in an open configuration. For example, in the fol-
lowing configuration, connect the terminator to the host unit and the
unit No.30, and do not connect terminators to unit Nos.0 to 29.
• Use terminators having a resistance of 120Ω (1/2 W). The total resis-
tance of both ends should be at least 54Ω .
Shielded cable
Match the communications specifications of the host computer and
E5AK 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 of
the E5AK controller. For details on the host computer, see the relevant
manual supplied with the host computer.
Set the communications specifications of the E5AK in the controller's
communications parameters. The communications parameters are set
on the front panel of the E5AK controller.
The following table shows the communications parameters (option
mode) provided on the E5AK controller and their respective settings.
Parameter/Symbol
A < B : Mark
A > B : Space
E5AK (No.0)
RS-485
No.
32 A
31 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)
E5AK (No.30)
RS-485
No.
32 A
B
31
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.