GE SRTP Driver

Overview

GE SRTP (Service Request Transport Protocol) — the Ethernet communication protocol for GE Fanuc Series 90 / RX3i / RX7i / VersaMax PLCs. PlantPulse Edge implements it with the NativeProcessDriver pattern: an external native client (GEClient) is spawned as a child process, and its standard output lines are parsed to accumulate values.

Item	Value
opc_type	GE
Implementation class	plantpulse.driver.protocol.ge.GEDriver
Communication library	External native binary (./GEClient, based on uGESRTP)
Inheritance	NativeProcessDriver
read	✅ (cache polling)
write	❌
Security	None
Default port	18245 (SRTP TCP) — specified via opc_agent_port

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Class Structure / Behavior

GEDriver
  └── ProcessTask (Thread)         — ProcessBuilder 로 ./GEClient ip port addresses timecycle
       └── Binder (Thread)         — 자식의 stdout 한 라인씩 파싱
            ↳ "VAL:<dev>:<idx>:<type>:<format>:<value>"  → current_value_map
            ↳ "START:" / "READ_FAIL:" / "ERROR:" / "LOG:" → 로그

• connect() — ICMP ping to NetUtils.isReachable(ip) → terminates immediately on failure. If the use-multi=true option is set and channel-thread is greater than 1, the address list is partitioned and multiple child processes are started concurrently.
• Child working directory: /opt/kopens/plantpulse-edge/plc/ge. Executable: ./GEClient.
• read() — returns the last value from current_value_map.get(addr + ":" + format) (the child updates it every timecycle).
• close() — process.destroyForcibly() of all ProcessTasks.

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OPC Registration Options

Field	Meaning	Default
opc_agent_ip / opc_agent_port	PLC IP / SRTP port (normally 18245)	—
timecycle	Polling period (ms) — passed to the child process as an argument	—
options.use-multi	Multi-process mode	true
options.channel-thread	Number of partitions (1 = single process)	1

Internal constant: GE_DEFAULT_CONNECTION_DELAY_MS = 1500 — wait after the first connect. If no tag is read for 10 seconds, START-ADDRESS-SCAN-SLOW logs a warning.

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Tag plc_address Format

Format passed to the child process (commaIOAddress): <dev>:<idx>:<data_type>:<format> joined by commas.

Notation	Meaning (GE Fanuc standard)
R00001	Register %R 1 (16-bit signed)
R00500	Register %R 500
I00001	Input bit %I 1
Q00001	Output bit %Q 1
T00001	Temporary memory %T
M00001	Internal coil %M
AI00001	Analog input
AQ00001	Analog output

format mapping (afterFormat):

format	Behavior
BIN[N]	Read the word, then extract bit N (N = 0..F, hex allowed)
STR	Word → 16-bit binary → ASCII text conversion
(otherwise)	The string sent by the child, as-is

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Unsupported Areas

• Write — write() is always false. Requires SRTP write to be exposed by the native client.
• Pure Java SRTP implementation — currently depends on an external binary. Moving in-process with the uGESRTP / iot-communication libraries is a follow-up task in the same direction as the LS driver (legacy .NET → Java).
• Symbolic Tag — only coordinates (area + index) are supported; named tags are not.
• Programming/Service Request mode — simple read queries only.

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Test Coverage

test/java/plantpulse/driver/protocol/ge/GEDriverTest — address conversion (commaIOAddress) and verification of the BIN/STR branches in afterFormat. The wire level is delegated to the external binary, so unit tests with a mock child process are handled separately.

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References

• GE Fanuc SRTP — public reverse engineering: uGESRTP, Wireshark dissector.
• Code: plantpulse-edge-driver/src/plantpulse/driver/protocol/ge/GEDriver.java.
• Operations: if the child binary is missing, the connect stage logs a PROCESS-SLOW warning plus a ERROR: log — first check whether /opt/kopens/plantpulse-edge/plc/ge/GEClient is executable (+x).