Serial Port Communications Capabilities - Emerson PACSystems RX3i User Manual

PACSystems™ RX3i and RSTi-EP CPU Reference Manual
GFK-2222AK
5.2.1

Serial Port Communications Capabilities

COM1 and COM2 can each be configured for one of the following modes. For details on
CPU configuration, refer to Section 3:.
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5.2.1.1 Features Supported
Feature
RTU Slave protocol
SNP Slave
Serial I/O – used with COMMREQs
Firmware Upgrade
(WinLoader utility)
Message Mode –used only with C blocks
(C Runtime Library Functions:
serial read, serial write, sscanf, sprintf)
RS-232
RS-485
66 Serial IO is the only protocol supported by CPE400.
Communications
RTU Slave – The port can be used for the Modbus RTU slave protocol. This mode also
permits connection to the port by an SNP master, such as the WinLoader utility or
the programming software. For details, refer to Section 6:, Serial I/O, SNP & RTU
Protocols.
Message Mode – The port is available for access by user logic. This enables C
language blocks to perform serial port I/O operations via C Runtime Library
functions.
Available – The port is not to be used by the CPU firmware.
SNP Slave – The port can only be used for the SNP slave protocol. For details, refer to
Section 6:, Serial I/O, SNP & RTU Protocols.
Serial I/O – The port can be used for general-purpose serial communication through
use of COMMREQ functions. For details, refer to Section 6:, Serial I/O, SNP & RTU
Protocols.
Serial Port 1 Serial Port 2
(COM1)
Yes
Yes
Yes
66
PLC in
STOP/No IO mode
Yes
Yes
No
Section 5
October 2019
(COM2)
Yes
Yes
Yes
No
Yes
No
Yes
125