
4SM2400 Serial- o-PLC Adap er User’s Guide
UG-SM2400–-177A–-02/2019
1. Introduction
The serial- o-PLC adap er is a simple way o ex end/replace an exis ing serial connec ion wi h a PLC wi hou hav-
ing o change any o her sof ware or hardware componen s. The adap er u ilizes pass- hrough firmware ha con-
ver s by es from a serial por o PLC and from PLC o serial por .
There are wo pass- hrough varian s:
ASCII ass-through: Copies all ASCII charac ers, which are received on he UART, verba im o he PLC line. Con-
versely, i forwards all ASCII charac ers received from he PLC line verba im o he UART. The ransmission o he
power line in ASCII pass-through is riggered by he recep ion of a special ASCII charac er, normally "End of Line"
or "Carriage Return" and can be changed on reques . The configura ion in ASCII pass-through mode can be
changed using AT commands.
TP ass-through: This varian of he pass- hrough firmware forwards all by es from he UART (no necessarily
ASCII) o he PLC line, and, conversely, forwards all by es received from he PLC line verba im o he UART. The
ransmission o he power line in TP pass-through mode is riggered by a ime-ou . Hence he name ‘Timeou -
based Packe iza ion (TP)’. The limi a ion of his mode is ha here is no way o change he configura ion.
No e: A his ime he ASCII pass-through and he TP pass-through firmware does no suppor he pro ocol used by
he Semi ech Graphical User In erface (GUI), which is available on mos o her firmware packages. Consequen ly, i
canno be used o communica e wi h he Serial- o-PLC adap er. Use serial erminal applica ions ins ead.
The SM2400 PLC device wi h ASCII pass-through or TP pass-through is ideal for indus rial con rol applica ions o
replace or ex end RS232 or RS485 connec ions wi hou having o modify o her par s of he sys ems or any of he
sof ware pro ocols.
A he end of his documen , wo SM2400-EVK2 adap ers wi h TP pass-through firmware are used as an example
of he serial- o-PLC adap er applica ion.
2. Features
• Replacemen of RS232 cable wi h DC or AC power line
• Replacemen of RS485 mul i-drop ne work wi h DC or AC power line
• Suppor s Modbus pro ocol
• Opera ional band: FCC (Cenelec-B/C version available)
• PLC PHY: OFDM (G3 FCC) or XXR (when addi ional performance is required)
• Effec ive PHY da a ra e up o 300 kbi /s (depending on band used)
• Serial por in erface speed: up o 625 kbi /s
• Packe size: up o 350 charac ers
• Seamless PLC ransmission wi h re ries o improve performance
• Fully ransparen mode (TP passthrough), plug and play coming ou of he box wi hou he need for any
programming
• Serial and PLC configura ion parame ers are accessible via AT commands (ASCII pass-through)