Phase 3 PR 46 -- DL205 BCD decoder (binary-coded-decimal numeric encoding). Adds ModbusDataType.Bcd16 and Bcd32 to the driver. Bcd16 is 1 register wide, Bcd32 is 2 registers wide; Bcd32 respects ModbusByteOrder (BigEndian/WordSwap) the same way Int32 does so the CDAB-style families (including DL205/DL260 themselves) can be configured. DecodeRegister uses the new internal DecodeBcd helper: walks each nibble from MSB to LSB, multiplies the running result by 10, adds the nibble as a decimal digit. Explicitly rejects nibbles > 9 with InvalidDataException -- hardware sometimes produces garbage during write-in-progress transitions and silently returning wrong numeric values would quietly corrupt the caller's data. EncodeRegister's new EncodeBcd inverts the operation (mod/div by 10 nibble-by-nibble) with an up-front overflow check against 10^nibbles-1. Why this matters for DL205/DL260: AutomationDirect DirectLOGIC uses BCD as the default numeric encoding for timers, counters, and operator-display numerics (not binary). A plain Int16 read of register 0x1234 returns 4660; the BCD path returns 1234. The two differ enough that silently defaulting to Int16 would give wildly wrong HMI values -- the caller must opt in to Bcd16/Bcd32 per tag. Unit tests: DecodeBcd (theory: 0,1,9,10,1234,9999), DecodeBcd_rejects_nibbles_above_nine, EncodeBcd (theory), Bcd16_decodes_DL205_register_1234_as_decimal_1234 (control: same bytes as Int16 decode to 4660), Bcd16_encode_round_trips_with_decode, Bcd16_encode_rejects_out_of_range_values, Bcd32_decodes_8_digits_big_endian, Bcd32_word_swap_handles_CDAB_layout, Bcd32_encode_round_trips_with_decode, Bcd_RegisterCount_matches_underlying_width. 66/66 Modbus.Tests pass. Integration test: DL205BcdQuirkTests.DL205_BCD16_decodes_HR1072_as_decimal_1234 against dl205.json pymodbus profile (HR[1072]=0x1234). Asserts Bcd16 decode=1234 AND Int16 decode=0x1234 on the same wire bytes to prove the paths are distinct. 3/3 DL205 integration tests pass with MODBUS_SIM_PROFILE=dl205.

2026-04-18 21:46:25 -04:00
parent cd19022d19
commit 8248b126ce
4 changed files with 226 additions and 2 deletions
--- a/tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests/DL205/DL205BcdQuirkTests.cs
+++ b/tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests/DL205/DL205BcdQuirkTests.cs
@@ -0,0 +1,56 @@
+using Shouldly;
+using Xunit;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests.DL205;
+
+/// <summary>
+///     Verifies DL205/DL260 binary-coded-decimal register handling against the
+///     <c>dl205.json</c> pymodbus profile. HR[1072] = 0x1234 on the profile represents
+///     decimal 1234 (BCD nibbles). Reading it as <see cref="ModbusDataType.Int16"/> would
+///     return 0x1234 = 4660; the <see cref="ModbusDataType.Bcd16"/> path decodes 1234.
+/// </summary>
+[Collection(ModbusSimulatorCollection.Name)]
+[Trait("Category", "Integration")]
+[Trait("Device", "DL205")]
+public sealed class DL205BcdQuirkTests(ModbusSimulatorFixture sim)
+{
+    [Fact]
+    public async Task DL205_BCD16_decodes_HR1072_as_decimal_1234()
+    {
+        if (sim.SkipReason is not null) Assert.Skip(sim.SkipReason);
+        if (!string.Equals(Environment.GetEnvironmentVariable("MODBUS_SIM_PROFILE"), "dl205",
+                StringComparison.OrdinalIgnoreCase))
+        {
+            Assert.Skip("MODBUS_SIM_PROFILE != dl205 — skipping (standard profile does not seed HR[1072]).");
+        }
+
+        var options = new ModbusDriverOptions
+        {
+            Host = sim.Host,
+            Port = sim.Port,
+            UnitId = 1,
+            Timeout = TimeSpan.FromSeconds(2),
+            Tags =
+            [
+                new ModbusTagDefinition("DL205_Count_Bcd",
+                    ModbusRegion.HoldingRegisters, Address: 1072,
+                    DataType: ModbusDataType.Bcd16, Writable: false),
+                new ModbusTagDefinition("DL205_Count_Int16",
+                    ModbusRegion.HoldingRegisters, Address: 1072,
+                    DataType: ModbusDataType.Int16, Writable: false),
+            ],
+            Probe = new ModbusProbeOptions { Enabled = false },
+        };
+        await using var driver = new ModbusDriver(options, driverInstanceId: "dl205-bcd");
+        await driver.InitializeAsync("{}", TestContext.Current.CancellationToken);
+
+        var results = await driver.ReadAsync(["DL205_Count_Bcd", "DL205_Count_Int16"],
+            TestContext.Current.CancellationToken);
+
+        results[0].StatusCode.ShouldBe(0u);
+        results[0].Value.ShouldBe(1234, "DL205 BCD register 0x1234 represents decimal 1234 per the DirectLOGIC convention");
+
+        results[1].StatusCode.ShouldBe(0u);
+        results[1].Value.ShouldBe((short)0x1234, "same register read as Int16 returns the raw 0x1234 = 4660 value — proves BCD path is distinct");
+    }
+}