Frame Configuration - Omron EJ1 User Manual

Frame Configuration

6-2

Frame Configuration

Note
Command Frame
Format
170
The communications protocol is CompoWay/F.
Commands from the host computer and responses from the EJ1 are con-
tained in data blocks called frames.
The structures of the command and response frames are described below.
In the following explanations, hexadecimal values are expressed by adding
the suffix H after the number, e.g., 02H.
All other alphanumeric values in the explanations indicate ASCII characters.
CompoWay/F
CompoWay/F is OMRON's standard communications format for general
serial communications.
It uses commands compliant with the well-established FINS used exten-
sively with OMRON Programmable Controllers together with a consistent
frame format to facilitate communications between more than one compo-
nent and between personal computers and components.
FINS (Factory Interface Network Service)
The FINS protocol provides message communications between control-
lers in OMRON FA networks.
Unit No. Sub-address
STX
02H
1 2
STX This code indicates the beginning of the communications
frame.
Always set to 02H.
Unit No. • Set the unit number that is set on SW1 and SW2 on the EJ1.
• Specify "XX" for a broadcast transmission. No responses will
be returned for broadcast transmissions.
• No responses will be returned from unit numbers other than
the ones in the above range.
Sub-address Not used by the EJ1. Always set to 0.
SID Not used by the EJ1. Always set to 0.
FINS-mini com- This text is the command. For details, refer to 6-3 FINS-mini
mand text Text.
ETX This code indicates the end of the communications frame.
Always set to 03H.
BCC The BCC calculation result from the unit number to the ETX.
Text
FINS-mini command text
S I D
0 0 0
2 1
BCC calculation range
Section 6-2
ETX BCC
03H
1 1