Host Link Mode; Protocol Macros - Omron CQM1H-SCB41 Operation Manual

Protocol Overview
1-2-1

Host Link Mode

Note
Sending C-mode Host Link Commands
Slave-initiated Communications
1-2-2

Protocol Macros

In Host Link Mode, C-mode Host Link commands can be sent from a com-
puter, PT, or other host to read or write I/O memory in the PC or to control the
PC's operating modes.
The TXD( ) instruction can be used to send ASCII data to the host. This is
called slave-initiated communications or unsolicited communications.
1. Programming Devices can also be connected in Host Link mode.
2. A 4-wire connection must be used when using an RS-422A/485 port.
Data
Data transfer procedures (called protocols) with general-purpose external
devices can be created as macros using the CX-Protocol to match the com-
munications specifications of the external device (but, half-duplex communi-
cations and start-stop synchronization must be used).
These protocols are stored in the Serial Communications Boards from the
CX-Protocol, and enable data to be exchanged with general-purpose external
devices simply by executing the PMCR( ) instruction in the CPU Unit.
Standard system protocols for exchanging data with OMRON devices (such
as Temperature Controllers, Intelligent Signal Processors, Bar Code Readers,
and Modems) are provided as a standard feature in the Serial Communica-
tions Boards and the CX-Protocol. The CX-Protocol can also be used to
change the standard system protocols according to user requirements.
Serial Communications Board
Note There are some restrictions in using the CX-Protocol to manipulate protocols
or perform other operations for the CQM1H-series Serial Communications
Board. These restrictions are described below.
Host computer
Serial Communications Board
Response
Host Link
command
Host computer
PC initiates communication.
CQM1H
Serial Communications Board
PMCR
( )
CQM1H
RS-232C
Message
Protocol made specifically for the
required communications specifications
Section 1-2
TXD( )
External device
with RS-232C port
5