Transmission Procedure - Omron E5AN User Manual

J Transmission
procedure
Host computer
E5AN/EN/CN/GN
J Interface
J Wiring
Host computer
RS-485
Abbr
FG
SG
A<B: [1] mark
A>B: [0] space
Both ends of the transmission line
(including the host computer) must be
specified (by setting terminator ON) as
the end node. The total resistance of
the terminators must be at least 54W.
When the host computer transmits a command frame, the E5AN/EN/CN/
GN transmits a response frame that corresponds to the command frame.
A single response frame is returned for each command frame. The follow-
ing diagram shows the operation of the command and response frames.
Command frame
Allow a wait time of at least 2 ms until the next command is sent after the
host computer receives a response from the E5AN/EN/CN/GN.
Communications with the host computer are carried out through a stan-
dard RS-485, RS-232C (RS-232C is only available with the E5AN/EN)
interface.
RS-485
· RS-485 connections can be 1 : 1 or 1 : N. A maximum of 32 Units (including
the host computer) can be connected in one-to-N systems.
· The total cable length is 500 m max.
· Use a shielded, twisted-pair cable AWG28 or larger for wiring the E5AN/
EN/CN, and AWG24 to AWG14 for wiring the E5GN.
--
+
Shielded cable
Response frame
E5AN/EN/CN/GN
RS-485
Pin No. Abbr
GN
AN/EN/CN
12 6 A(--)
11 5 B(+)
E5AN/EN/CN/GN
Terminator
end node
120W
RS-485
(1/2W)
Pin No. Abbr
AN/EN/CN
12
11
Use a terminator of resistance
Shielded cable
120W = (1/2W).
1.1 Outline
Command frame
Communications transceiver
6.8V
GN
6 A(--)
5 B(+)
TX
RX
1--3