adesto SM2400-EVK2 사용자 설명서 - 페이지 4

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1. Introduction

The serial-to-PLC adapter is a simple way to extend/replace an existing serial connection with a PLC without hav-

ing to change any other software or hardware components. The adapter utilizes pass-through firmware that con-

verts bytes from a serial port to PLC and from PLC to serial port.

There are two pass-through variants:

ASCII pass-through: Copies all ASCII characters, which are received on the UART, verbatim to the PLC line. Con-

versely, it forwards all ASCII characters received from the PLC line verbatim to the UART. The transmission to the

power line in ASCII pass-through is triggered by the reception of a special ASCII character, normally "End of Line"

or "Carriage Return" and can be changed on request. The configuration in ASCII pass-through mode can be

changed using AT commands.

TP pass-through: This variant of the pass-through firmware forwards all bytes from the UART (not necessarily

ASCII) to the PLC line, and, conversely, forwards all bytes received from the PLC line verbatim to the UART. The

transmission to the power line in TP pass-through mode is triggered by a time-out. Hence the name 'Timeout-

based Packetization (TP)'. The limitation of this mode is that there is no way to change the configuration.

Note: At this time the ASCII pass-through and the TP pass-through firmware does not support the protocol used by

the Semitech Graphical User Interface (GUI), which is available on most other firmware packages. Consequently, it

cannot be used to communicate with the Serial-to-PLC adapter. Use serial terminal applications instead.

The SM2400 PLC device with ASCII pass-through or TP pass-through is ideal for industrial control applications to

replace or extend RS232 or RS485 connections without having to modify other parts of the systems or any of the

software protocols.

At the end of this document, two SM2400-EVK2 adapters with TP pass-through firmware are used as an example

of the serial-to-PLC adapter application.

• Replacement of RS232 cable with DC or AC power line

• Replacement of RS485 multi-drop network with DC or AC power line

• Supports Modbus protocol

• Operational band: FCC (Cenelec-B/C version available)

• PLC PHY: OFDM (G3 FCC) or XXR (when additional performance is required)

• Effective PHY data rate up to 300 kbit/s (depending on band used)

• Serial port interface speed: up to 625 kbit/s

• Packet size: up to 350 characters

• Seamless PLC transmission with retries to improve performance

• Fully transparent mode (TP passthrough), plug and play coming out of the box without the need for any

programming

• Serial and PLC configuration parameters are accessible via AT commands (ASCII pass-through)

SM2400 Serial-to-PLC Adapter User's Guide

UG-SM2400–-177A–-02/2019