FATEK FBs Driver

Overview

ASCII communication for FATEK FACON FBs series PLCs. Custom implementation based on the public specification in the FBs Series Communication Protocol Manual. No dependency on external libraries or GitHub code.

Item	Value
opc_type	FATEK
Implementation class	plantpulse.driver.protocol.fatek.FatekDriver
Library	(none — custom implementation. FATEK FBs manual)
read	Good (cmd 44 / 46)
write	Good (cmd 45 / 47)
Default port	500
Security	None

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Classes / Structure

FatekDriver  (BaseProtocolDriver)
 ├── Socket / InputStream / OutputStream
 ├── station                — 0~255 (디폴트 1)
 ├── synchronized read/write
 ├── Addr (device, index, bit)
 ├── parseAddress(raw)      — R/D/M/X/Y/T/C/WX/WY/WM
 ├── formatBitItem / formatWordItem
 └── sendAndReceive(cmd, body) — STX/ETX/LRC 검증

Immediately after connect(), cmd 41 (status) is called as a hello, but the connection is maintained even if it fails (the PLC may not support it).

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Wire Format Summary

Request : STX <station 2hex> <cmd 2hex> <data ASCII> <LRC 2hex> ETX
Response: STX <station 2hex> <cmd 2hex> <error-1char> <data> <LRC 2hex> ETX
STX = 0x02, ETX = 0x03
LRC : STX 다음부터 LRC 직전까지 XOR (ASCII char 단위) → 2자리 hex 대문자

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Main Commands

cmd	Action
40	Read system status
41	Get PLC run/stop/error/break status (for hello)
42	Run/Stop PLC
44	Read data from registers (consecutive words)
45	Write data to registers (consecutive words)
46	Read individual data (single bit / mixed)
47	Write individual data

In sendAndReceive(), if the response error code is not '0', then IOException (e.g. '2' illegal value, '4' illegal command, '5' checksum, '6' illegal address, 'A' PLC password locked).

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OPC Registration Options (options)

Key	Meaning	Default
station	PLC station ID (0–255)	1
connect-timeout	ms	3000
read-timeout	ms	3000

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Tag Address Format

Notation	Meaning	bit/word
R0 / R100	General register	word
D100	Data register	word
WX10 / WY0 / WM10	Input/Output/Internal word	word
M100	Internal relay	bit
X0 / Y0 / S0	Input / Output / Step	bit
T0 / C0	Timer / Counter present value	word (RT/RC notation of cmd 44)

formatWordItem() :

• R/D → <dev>+5자 index (6 characters total)
• WX/WY/WM → <dev>+4자 (6 characters total)
• T → RT + 4 characters, C → RC + 4 characters

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Data Encoding / Decoding

wordCountFor(dt, fmt) determines 1/2/4 words. decodeWords() performs the conversion — FATEK FB multi-word values use little-endian word order (low word first).

format / data_type	Word count	Notes
W / WORD / UI / UW	1	signed/unsigned 16
B / BYTE	1	(16-bit response as-is)
DW / DWORD / Int32	2	signed 32
UDW / UInt32	2	unsigned 32
REAL / FLOAT / Float	2	IEEE 32-bit
LREAL / DOUBLE / Double	4	IEEE 64-bit
LW / LWORD / Int64	4	signed 64

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Supported / Not Supported

• ✅ cmd 44 / 45 (consecutive read/write of N words)
• ✅ cmd 46 / 47 (single-bit read/write)
• ✅ STX/ETX/LRC frame validation + station/cmd echo validation
• ✅ 32 / 64-bit multi-word, Float, Double
• ❌ Simultaneous read/write of multiple bits (mixed items of cmd 46/47)
• ❌ Run/Stop PLC (cmd 42)
• ❌ Separate Timer/Counter contact bits (currently word only)

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Test Coverage

test/java/plantpulse/driver/protocol/fatek/

Class	Test count
FatekDriverTest	48

48 tests total — LRC, buildRequest, address parser, word encode/decode, error codes.

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References

• FATEK FBs Series Communication Protocol Manual (vendor public)
• Code: src/plantpulse/driver/protocol/fatek/FatekDriver.java