Joseph Doherty cde018aec1 Phase 3 PR 52 -- Modbus exception-code -> OPC UA StatusCode translation. Before this PR every server-side Modbus exception AND every transport-layer failure collapsed to BadInternalError (0x80020000) in the driver's Read/Write results, making field diagnosis 'is this a tag misconfig or a driver bug?' impossible from the OPC UA client side. PR 52 adds a MapModbusExceptionToStatus helper that translates per spec: 01 Illegal Function -> BadNotSupported (0x803D0000); 02 Illegal Data Address -> BadOutOfRange (0x803C0000); 03 Illegal Data Value -> BadOutOfRange; 04 Server Failure -> BadDeviceFailure (0x80550000); 05/06 Acknowledge/Busy -> BadDeviceFailure; 0A/0B Gateway -> BadCommunicationError (0x80050000); unknown -> BadInternalError fallback. Non-Modbus failures (socket drop, timeout, malformed frame) in ReadAsync are now distinguished from tag-level faults: they map to BadCommunicationError so operators check network/PLC reachability rather than tag definitions. Why per-DL205: docs/v2/dl205.md documents DL205/DL260 returning only codes 01-04 with specific triggers -- exception 04 specifically means 'CPU in PROGRAM mode during a protected write', which is operator-recoverable by switching the CPU to RUN; surfacing it as BadDeviceFailure (not BadInternalError) makes the fix obvious. Changes in ModbusDriver: Read catch-chain now ModbusException first (-> mapper), generic Exception second (-> BadCommunicationError); Write catch-chain same pattern but generic Exception stays BadInternalError because write failures can legitimately come from EncodeRegister (out-of-range value) which is a driver-layer fault. Unit tests: MapModbusExceptionToStatus theory exercising every code in the table including the 0xFF fallback; Read_surface_exception_02_as_BadOutOfRange with an ExceptionRaisingTransport that forces code 02; Write_surface_exception_04_as_BadDeviceFailure for CPU-mode faults; Read_non_modbus_failure_maps_to_BadCommunicationError with a NonModbusFailureTransport that raises EndOfStreamException. 115/115 Modbus.Tests pass. Integration test: DL205ExceptionCodeTests.DL205_FC03_at_unmapped_register_returns_BadOutOfRange reads HR[16383] which is beyond the seeded uint16 cells on the dl205.json profile; pymodbus returns exception 02 and the driver surfaces BadOutOfRange. 11/11 DL205 integration tests pass with MODBUS_SIM_PROFILE=dl205.

2026-04-18 22:28:37 -04:00

..

DL205

Phase 3 PR 52 -- Modbus exception-code -> OPC UA StatusCode translation. Before this PR every server-side Modbus exception AND every transport-layer failure collapsed to BadInternalError (0x80020000) in the driver's Read/Write results, making field diagnosis 'is this a tag misconfig or a driver bug?' impossible from the OPC UA client side. PR 52 adds a MapModbusExceptionToStatus helper that translates per spec: 01 Illegal Function -> BadNotSupported (0x803D0000); 02 Illegal Data Address -> BadOutOfRange (0x803C0000); 03 Illegal Data Value -> BadOutOfRange; 04 Server Failure -> BadDeviceFailure (0x80550000); 05/06 Acknowledge/Busy -> BadDeviceFailure; 0A/0B Gateway -> BadCommunicationError (0x80050000); unknown -> BadInternalError fallback. Non-Modbus failures (socket drop, timeout, malformed frame) in ReadAsync are now distinguished from tag-level faults: they map to BadCommunicationError so operators check network/PLC reachability rather than tag definitions. Why per-DL205: docs/v2/dl205.md documents DL205/DL260 returning only codes 01-04 with specific triggers -- exception 04 specifically means 'CPU in PROGRAM mode during a protected write', which is operator-recoverable by switching the CPU to RUN; surfacing it as BadDeviceFailure (not BadInternalError) makes the fix obvious. Changes in ModbusDriver: Read catch-chain now ModbusException first (-> mapper), generic Exception second (-> BadCommunicationError); Write catch-chain same pattern but generic Exception stays BadInternalError because write failures can legitimately come from EncodeRegister (out-of-range value) which is a driver-layer fault. Unit tests: MapModbusExceptionToStatus theory exercising every code in the table including the 0xFF fallback; Read_surface_exception_02_as_BadOutOfRange with an ExceptionRaisingTransport that forces code 02; Write_surface_exception_04_as_BadDeviceFailure for CPU-mode faults; Read_non_modbus_failure_maps_to_BadCommunicationError with a NonModbusFailureTransport that raises EndOfStreamException. 115/115 Modbus.Tests pass. Integration test: DL205ExceptionCodeTests.DL205_FC03_at_unmapped_register_returns_BadOutOfRange reads HR[16383] which is beyond the seeded uint16 cells on the dl205.json profile; pymodbus returns exception 02 and the driver surfaces BadOutOfRange. 11/11 DL205 integration tests pass with MODBUS_SIM_PROFILE=dl205.

2026-04-18 22:28:37 -04:00

Pymodbus

Phase 3 PR 51 -- DL260 X-input FC02 discrete-input mapping end-to-end test. Integration test DL205XInputTests reads FC02 at the DirectLogicAddress.XInputToDiscrete-resolved address and asserts two behaviors against the dl205.json pymodbus profile: (1) X20 octal (=decimal 16 = Modbus DI 16) reads ON, proving the helper correctly octal-parses the trailing number and adds it to the 0 base; (2) X21 octal reads OFF (not exception) -- per docs/v2/dl205.md §I/O-mapping, 'reading a non-populated X input returns zero, not an exception' on DL260, because the CPU sizes the discrete-input table to the configured I/O not the installed hardware. Pymodbus models this by returning the default 0 value for any DI bit in the configured 'di size' range that wasn't explicitly seeded, matching real DL260 behaviour. Test uses X20 rather than X0 to sidestep a shared-blocks conflict: pymodbus places FC01/FC02 bit-address 0..15 into cell 0, but cell 0 is already uint16-typed (V0 marker = 0xCAFE) per the register-zero quirk test, and shared-blocks semantics allow only one type per cell. X20 octal = DI 16 lands in cell 1 which is free, so both the V0 quirk AND the X-input quirk can coexist in one profile. dl205.json: bits cell 1 seeded value=9 (bits 0 and 3 set -> X20, X23 octal = ON), write-range extended to include cell 1 (though X-inputs are read-only; the write-range entry is required by pymodbus for ANY cell referenced in a bits section even if only reads are expected -- pymodbus validates write-access uniformly). 10/10 DL205 integration tests pass with MODBUS_SIM_PROFILE=dl205. No driver code changes -- the XInputToDiscrete helper + FC02 read path already landed in PRs 50 and 21 respectively. This PR closes the integration-test gap that docs/v2/dl205.md called out under test name DL205_Xinput_unpopulated_reads_as_zero.

2026-04-18 22:25:13 -04:00

ModbusSimulatorFixture.cs

Phase 3 PR 43 — followup commit: validate pymodbus simulator end-to-end + fix three real bugs surfaced by running it. winget-installed Python 3.12.10 + pip-installed pymodbus[simulator]==3.13.0 on the dev box; both profiles boot cleanly, the integration-suite smoke test passes against either profile.

2026-04-18 21:14:02 -04:00

ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests.csproj

Phase 3 PR 43 — Swap ModbusPal to pymodbus for the integration-test simulator. Replaces the .xmpp profiles shipped in PR 42 with pymodbus 3.13.0 ModbusSimulatorServer JSON configs in tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests/Pymodbus/. Substantive reasons for the swap (rationale block in the test-plan doc): ModbusPal 1.6b is abandoned (last release ~2019), Java GUI-only with no headless mode in the official JAR, and only exposes 2 of the 4 standard Modbus tables (holding_registers + coils — no input_registers, no discrete_inputs). pymodbus is current stable, pure Python CLI (pip install pymodbus[simulator]==3.13.0), exposes all four tables, has built-in declarative actions (increment / random / timestamp / uptime) for dynamic registers, supports custom Python actions for anything more complex, and ships an optional aiohttp-based web UI / REST API for live inspection. Pip-installable on Windows; sidesteps the privileged-port admin requirement by defaulting to TCP 5020.

2026-04-18 20:35:26 -04:00