fix(historian): #679 Gateway — Average/Count not supported (no AVEVA equivalent), TimeAverage → TimeWeightedAverage

This commit is contained in:
Joseph Doherty
2026-10-11 15:19:19 -04:00
parent 6d5c1c768b
commit fb5ec80fe6
7 changed files with 56 additions and 22 deletions
@@ -84,8 +84,8 @@ public sealed class GatewayHistorianDataSource : IHistorianDataSource, IAsyncDis
var mode = AggregateModeMapper.ToRetrievalMode(aggregate);
try
{
// Total/Count are now native gateway retrieval modes — no client-side scaling
// (unlike the Wonderware path that derived Total as Average × interval-seconds).
// Total is a native gateway retrieval mode (Integral) — no client-side scaling. Average and Count
// have no AVEVA mode and were rejected by the mapper above (#679).
var buckets = new List<HistorianAggregateSample>();
await foreach (var bucket in _client
.ReadAggregateAsync(fullReference, startUtc, endUtc, mode, interval, cancellationToken)
@@ -9,15 +9,15 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Mapping;
/// </summary>
/// <remarks>
/// <para>
/// Average/Minimum/Maximum line up with the legacy Wonderware client's aggregate mapping. The two
/// remaining members are now served by <b>native</b> gateway retrieval modes:
/// <see cref="HistoryAggregateType.Total"/> → <see cref="RetrievalMode.Integral"/> and
/// <see cref="HistoryAggregateType.Count"/> → <see cref="RetrievalMode.Counter"/>.
/// Served: <see cref="HistoryAggregateType.TimeAverage"/> → <see cref="RetrievalMode.TimeWeightedAverage"/>,
/// Minimum → <see cref="RetrievalMode.MinimumWithTime"/>, Maximum → <see cref="RetrievalMode.MaximumWithTime"/>,
/// Total → <see cref="RetrievalMode.Integral"/>.
/// </para>
/// <para>
/// This replaces the Wonderware-era client-side workarounds (Total derived as Average × interval,
/// Count approximated from a value count): no client-side scaling is performed any more, so the
/// gateway path is a strict improvement.
/// Deliberately NOT served (#679): <see cref="HistoryAggregateType.Average"/> (OPC UA Average is the arithmetic mean;
/// AVEVA's modes include no arithmetic mean — only the time-weighted one, which is TimeAverage) and
/// <see cref="HistoryAggregateType.Count"/> (AVEVA <c>Counter</c> is a rollover-counter increase, not a sample count).
/// Both surface as <c>BadAggregateNotSupported</c> rather than returning a different statistic under the requested name.
/// </para>
/// </remarks>
internal static class AggregateModeMapper
@@ -29,11 +29,10 @@ internal static class AggregateModeMapper
/// <exception cref="ArgumentOutOfRangeException">An undefined enum value.</exception>
public static RetrievalMode ToRetrievalMode(HistoryAggregateType aggregate) => aggregate switch
{
HistoryAggregateType.Average => RetrievalMode.TimeWeightedAverage,
HistoryAggregateType.TimeAverage => RetrievalMode.TimeWeightedAverage,
HistoryAggregateType.Minimum => RetrievalMode.MinimumWithTime,
HistoryAggregateType.Maximum => RetrievalMode.MaximumWithTime,
HistoryAggregateType.Total => RetrievalMode.Integral,
HistoryAggregateType.Count => RetrievalMode.Counter,
// Part 13 aggregates the gateway has no retrieval mode for (#285) — an UNDEFINED enum value is a
// programming error, but a defined-yet-unserved member is a normal client request the server
// answers with BadAggregateNotSupported.