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Phase 3 PR 46 -- DL205 BCD decoder #45

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dohertj2 merged 1 commits from phase-3-pr46-dl205-bcd into v2 2026-04-18 22:13:26 -04:00
Conversation 0 Commits 1 Files Changed 4 +226 -2
4 changed files with 226 additions and 2 deletions
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67
src/ZB.MOM.WW.OtOpcUa.Driver.Modbus/ModbusDriver.cs
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@@ -404,8 +404,8 @@ public sealed class ModbusDriver(ModbusDriverOptions options, string driverInsta
/// </summary>
internal static ushort RegisterCount(ModbusTagDefinition tag) => tag.DataType switch
{
ModbusDataType.Int16 or ModbusDataType.UInt16 or ModbusDataType.BitInRegister => 1,
ModbusDataType.Int32 or ModbusDataType.UInt32 or ModbusDataType.Float32 => 2,
ModbusDataType.Int16 or ModbusDataType.UInt16 or ModbusDataType.BitInRegister or ModbusDataType.Bcd16 => 1,
ModbusDataType.Int32 or ModbusDataType.UInt32 or ModbusDataType.Float32 or ModbusDataType.Bcd32 => 2,
ModbusDataType.Int64 or ModbusDataType.UInt64 or ModbusDataType.Float64 => 4,
ModbusDataType.String => (ushort)((tag.StringLength + 1) / 2), // 2 chars per register
_ => throw new InvalidOperationException($"Non-register data type {tag.DataType}"),
@@ -435,6 +435,17 @@ public sealed class ModbusDriver(ModbusDriverOptions options, string driverInsta
{
case ModbusDataType.Int16: return BinaryPrimitives.ReadInt16BigEndian(data);
case ModbusDataType.UInt16: return BinaryPrimitives.ReadUInt16BigEndian(data);
case ModbusDataType.Bcd16:
{
var raw = BinaryPrimitives.ReadUInt16BigEndian(data);
return (int)DecodeBcd(raw, nibbles: 4);
}
case ModbusDataType.Bcd32:
{
var b = NormalizeWordOrder(data, tag.ByteOrder);
var raw = BinaryPrimitives.ReadUInt32BigEndian(b);
return (int)DecodeBcd(raw, nibbles: 8);
}
case ModbusDataType.BitInRegister:
{
var raw = BinaryPrimitives.ReadUInt16BigEndian(data);
@@ -510,6 +521,21 @@ public sealed class ModbusDriver(ModbusDriverOptions options, string driverInsta
var v = Convert.ToUInt16(value);
var b = new byte[2]; BinaryPrimitives.WriteUInt16BigEndian(b, v); return b;
}
case ModbusDataType.Bcd16:
{
var v = Convert.ToUInt32(value);
if (v > 9999) throw new OverflowException($"BCD16 value {v} exceeds 4 decimal digits");
var raw = (ushort)EncodeBcd(v, nibbles: 4);
var b = new byte[2]; BinaryPrimitives.WriteUInt16BigEndian(b, raw); return b;
}
case ModbusDataType.Bcd32:
{
var v = Convert.ToUInt32(value);
if (v > 99_999_999u) throw new OverflowException($"BCD32 value {v} exceeds 8 decimal digits");
var raw = EncodeBcd(v, nibbles: 8);
var b = new byte[4]; BinaryPrimitives.WriteUInt32BigEndian(b, raw);
return NormalizeWordOrder(b, tag.ByteOrder);
}
case ModbusDataType.Int32:
{
var v = Convert.ToInt32(value);
@@ -579,9 +605,46 @@ public sealed class ModbusDriver(ModbusDriverOptions options, string driverInsta
ModbusDataType.Float32 => DriverDataType.Float32,
ModbusDataType.Float64 => DriverDataType.Float64,
ModbusDataType.String => DriverDataType.String,
ModbusDataType.Bcd16 or ModbusDataType.Bcd32 => DriverDataType.Int32,
_ => DriverDataType.Int32,
};
/// <summary>
/// Decode an N-nibble binary-coded-decimal value. Each nibble of <paramref name="raw"/>
/// encodes one decimal digit (most-significant nibble first). Rejects nibbles &gt; 9 —
/// the hardware sometimes produces garbage during transitions and silent non-BCD reads
/// would quietly corrupt the caller's data.
/// </summary>
internal static uint DecodeBcd(uint raw, int nibbles)
{
uint result = 0;
for (var i = nibbles - 1; i >= 0; i--)
{
var digit = (raw >> (i * 4)) & 0xF;
if (digit > 9)
throw new InvalidDataException(
$"Non-BCD nibble 0x{digit:X} at position {i} of raw=0x{raw:X}");
result = result * 10 + digit;
}
return result;
}
/// <summary>
/// Encode a decimal value as N-nibble BCD. Caller is responsible for range-checking
/// against the nibble capacity (10^nibbles - 1).
/// </summary>
internal static uint EncodeBcd(uint value, int nibbles)
{
uint result = 0;
for (var i = 0; i < nibbles; i++)
{
var digit = value % 10;
result |= digit << (i * 4);
value /= 10;
}
return result;
}
private IModbusTransport RequireTransport() =>
_transport ?? throw new InvalidOperationException("ModbusDriver not initialized");

12
src/ZB.MOM.WW.OtOpcUa.Driver.Modbus/ModbusDriverOptions.cs
View File

@@ -89,6 +89,18 @@ public enum ModbusDataType
BitInRegister,
/// <summary>ASCII string packed 2 chars per register, <see cref="ModbusTagDefinition.StringLength"/> characters long.</summary>
String,
/// <summary>
/// 16-bit binary-coded decimal. Each nibble encodes one decimal digit (0-9). Register
/// value <c>0x1234</c> decodes as decimal <c>1234</c> — NOT binary <c>0x04D2 = 4660</c>.
/// DL205/DL260 and several Mitsubishi / Omron families store timers, counters, and
/// operator-facing numerics as BCD by default.
/// </summary>
Bcd16,
/// <summary>
/// 32-bit (two-register) BCD. Decodes 8 decimal digits. Word ordering follows
/// <see cref="ModbusTagDefinition.ByteOrder"/> the same way <see cref="Int32"/> does.
/// </summary>
Bcd32,
}
/// <summary>

56
tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests/DL205/DL205BcdQuirkTests.cs Normal file
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@@ -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");
}
}

93
tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests/ModbusDataTypeTests.cs
View File

@@ -219,4 +219,97 @@ public sealed class ModbusDataTypeTests
ModbusDriver.DecodeRegister(wire, hi).ShouldBe("He");
ModbusDriver.DecodeRegister(wire, lo).ShouldBe("eH");
}
// --- BCD (binary-coded decimal, DL205/DL260 default numeric encoding) ---
[Theory]
[InlineData(0x0000u, 0u)]
[InlineData(0x0001u, 1u)]
[InlineData(0x0009u, 9u)]
[InlineData(0x0010u, 10u)]
[InlineData(0x1234u, 1234u)]
[InlineData(0x9999u, 9999u)]
public void DecodeBcd_16_bit_decodes_expected_decimal(uint raw, uint expected)
=> ModbusDriver.DecodeBcd(raw, nibbles: 4).ShouldBe(expected);
[Fact]
public void DecodeBcd_rejects_nibbles_above_nine()
{
Should.Throw<InvalidDataException>(() => ModbusDriver.DecodeBcd(0x00A5u, nibbles: 4))
.Message.ShouldContain("Non-BCD nibble");
}
[Theory]
[InlineData(0u, 0x0000u)]
[InlineData(5u, 0x0005u)]
[InlineData(42u, 0x0042u)]
[InlineData(1234u, 0x1234u)]
[InlineData(9999u, 0x9999u)]
public void EncodeBcd_16_bit_encodes_expected_nibbles(uint value, uint expected)
=> ModbusDriver.EncodeBcd(value, nibbles: 4).ShouldBe(expected);
[Fact]
public void Bcd16_decodes_DL205_register_1234_as_decimal_1234()
{
// HR[1072] = 0x1234 on the DL205 profile represents decimal 1234. A plain Int16 decode
// would return 0x04D2 = 4660 — proof the BCD path is different.
var tag = new ModbusTagDefinition("T", ModbusRegion.HoldingRegisters, 0, ModbusDataType.Bcd16);
ModbusDriver.DecodeRegister(new byte[] { 0x12, 0x34 }, tag).ShouldBe(1234);
var int16Tag = tag with { DataType = ModbusDataType.Int16 };
ModbusDriver.DecodeRegister(new byte[] { 0x12, 0x34 }, int16Tag).ShouldBe((short)0x1234);
}
[Fact]
public void Bcd16_encode_round_trips_with_decode()
{
var tag = new ModbusTagDefinition("T", ModbusRegion.HoldingRegisters, 0, ModbusDataType.Bcd16);
var wire = ModbusDriver.EncodeRegister(4321, tag);
wire.ShouldBe(new byte[] { 0x43, 0x21 });
ModbusDriver.DecodeRegister(wire, tag).ShouldBe(4321);
}
[Fact]
public void Bcd16_encode_rejects_out_of_range_values()
{
var tag = new ModbusTagDefinition("T", ModbusRegion.HoldingRegisters, 0, ModbusDataType.Bcd16);
Should.Throw<OverflowException>(() => ModbusDriver.EncodeRegister(10000, tag))
.Message.ShouldContain("4 decimal digits");
}
[Fact]
public void Bcd32_decodes_8_digits_big_endian()
{
// 0x12345678 as BCD = decimal 12_345_678.
var tag = new ModbusTagDefinition("T", ModbusRegion.HoldingRegisters, 0, ModbusDataType.Bcd32);
ModbusDriver.DecodeRegister(new byte[] { 0x12, 0x34, 0x56, 0x78 }, tag).ShouldBe(12_345_678);
}
[Fact]
public void Bcd32_word_swap_handles_CDAB_layout()
{
// PLC stored 12_345_678 with word swap: low-word 0x5678 first, high-word 0x1234 second.
// Wire bytes [0x56, 0x78, 0x12, 0x34] + WordSwap → decode to decimal 12_345_678.
var tag = new ModbusTagDefinition("T", ModbusRegion.HoldingRegisters, 0, ModbusDataType.Bcd32,
ByteOrder: ModbusByteOrder.WordSwap);
ModbusDriver.DecodeRegister(new byte[] { 0x56, 0x78, 0x12, 0x34 }, tag).ShouldBe(12_345_678);
}
[Fact]
public void Bcd32_encode_round_trips_with_decode()
{
var tag = new ModbusTagDefinition("T", ModbusRegion.HoldingRegisters, 0, ModbusDataType.Bcd32);
var wire = ModbusDriver.EncodeRegister(87_654_321u, tag);
wire.ShouldBe(new byte[] { 0x87, 0x65, 0x43, 0x21 });
ModbusDriver.DecodeRegister(wire, tag).ShouldBe(87_654_321);
}
[Fact]
public void Bcd_RegisterCount_matches_underlying_width()
{
var b16 = new ModbusTagDefinition("A", ModbusRegion.HoldingRegisters, 0, ModbusDataType.Bcd16);
var b32 = new ModbusTagDefinition("B", ModbusRegion.HoldingRegisters, 0, ModbusDataType.Bcd32);
ModbusDriver.RegisterCount(b16).ShouldBe((ushort)1);
ModbusDriver.RegisterCount(b32).ShouldBe((ushort)2);
}
}