Omron CQM1H-SCB41 Host Link Mode, Protocol Macros, Sending C-mode Host Link Commands

Protocol Overview Section 1-2

1-2-1 Host Link Mode

In Host Link Mode, C-mode Host Link commands can be sent from a computer, PT, or other host to read or write I/O memory in the PC or to control the PC’s oper- ating modes.

The TXD(––) instruction can be used to send ASCII data to the host. This is called slave-initiated communications or unsolicited communications.

Note 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.

Sending C-mode Host Link Commands

Host computer

Serial Communications Board

Response

Host Link command

Slave-initiated Communications

Host computer

TXD(––)

PC initiates communication.

Data

CQM1H Serial Communications Board

1-2-2 Protocol Macros

Data transfer procedures (called protocols) with general-purpose external de- vices can be created as macros using the CX-Protocol to match the communica- tions specifications of the external device (but, half-duplex communications 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 de- vices 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 Communications 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

PMCR (––)

CQM1H

External device

with RS-232C port

RS-232C

Message

Protocol made specifically for the required communications specifications

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.

5