Protocol Macros; Loopback Test; Serial Gateway Mode - Omron CJ1W-SCU32 Operation Manual

1 Introduction
1-3-1

Protocol Macros

In Protocol Macro Mode. the Serial Communications Unit uses the data transfer procedures (proto-
cols) that are created by CX-Protocol to communicate with general-purpose external devices. The
protocols can be created so as to match the communications specifications (half-duplex or full-
duplex, and start-stop synchronization) of external devices.
These protocols are stored in the Serial Communications Unit, and enable data to be exchanged
with general-purpose external devices simply through execution of the ExecPMCR instruction in the
CPU Unit.
Standard system protocols to exchange data with OMRON devices (such as Temperature Control-
lers, Intelligent Signal Processors, Bar Code Readers, and Modems) are provided as a standard
feature in the CX-Protocol and the Serial Communications Unit. You can also use CX-Protocol to
change the standard system protocols according to user requirements.
Serial Communications Unit
1-3-2

Loopback Test

The loopback test is a testing function for communications circuits. The Serial Communications Unit
compares transmitted data and loopback data. To perform loopback tests, connect a loopback wire con-
nector to the port of the Serial Communications Unit.
This loopback test is performed inside the specified serial communications port. It is not a loopback test
using the RS-232C or RS-422A/485 communications path.

Loopback test

1-3-3

Serial Gateway Mode

The received message is automatically converted to either CompoWay/F, Modbus-RTU, or Modbus-
ASCII, depending on the type of message.
CompoWay/F, Modbus-RTU, and Modbus-ASCII
Serial
Communications
Unit
CompoWay
1-6
ExecPMCR
Communications sequence
Protocol
Loopback test switch
The loopback test results
are stored.
SendCmd
Serial
Header CompoWay/F
Gateway
CompoWay-compatible
OMRON component,
Modbus-RTU-, or Modbus
ASCII-compatible device
CJ-series Serial Communications Units Operation Manual for NJ-series CPU Unit(W494)
General-purpose external device
Modbus-RTU/
Modbus-ASCII
command