| Success = 0 | Operation successful. |
| Failed = -1 | Operation failed. |
| Timeout = -2 | Operation failed due to timeout. |
| NotConnected = -3 | Not connected to Historian server. |
| CollectorNotFound = -4 | The given collector does not exist on the server. |
| NotSupported = -5 | Operation not supported. |
| DuplicateData = -6 | Attempt to overwrite an existing data sample. |
| InvalidUsername = -7 | Bad user name or password. |
| AccessDenied = -8 | Insufficient permissions for operation. |
| WriteInFuture = -9 | Attempted data write too far in the future. |
| WriteArchiveOffline = -10 | Attempted data write to an offline archive. |
| WriteArchiveReadonly = -11 | Attempted data write to a read-only archive. |
| WriteOutsideActiveRange = -12 | Attempted data write beyond the configured active range. |
| WriteNoArchiveAvailable = -13 | Attempted data write with no available archives. |
| InvalidTagname = -14 | The requested tag was not found. |
| LicensedTagCountExceeded = -15 | Number of licensed tags exceeded. |
| LicensedConnectionCountExceeded = -16 | Number of licensed server connections exceeded. |
| InternalLicenseError = -17 | Internal license error. |
| NoValue = -18 | No available tag data. |
| DuplicateCollector = -19 | The given collector name already exists on the server. |
| NotLicensed = -20 | Server or feature is not licensed. |
| CircularReference = -21 | Circular reference detected in calculation. |
| BackupInsufficientSpace = -22 | Insufficient disk space to perform backup. |
| InvalidServerVersion = -23 | Operation unsupported due to server version. |
| QueryResultSizeExceeded = -24 | Upper limit on query results exceeded. |
| DeleteOutsideActiveRange = -25 | Attempted data delete outside allowed modification interval. |
| AlarmArchiverUnavailable = -26 | Alarms and Events subsystem unreachable. |
| ArgumentException = -27 | A supplied argument is invalid. |
| ArgumentNullException = -28 | A supplied argument is NULL. |
| ArgumentOutOfRangeException = -29 | A supplied argument is outside the valid range. |
| InvalidEnumeratedSet = -30 | The requested Enumerated Set was not found. |
| InvalidDataStore = -31 | The requested data store was not found. |
| NotPermitted = -32 | Operation not permitted. |
| InvalidCustomDataType = -33 | The Custom data type is not supported. |
| ihSTATUS_EXISTING_USERDEF_REFERENCES = -34 | N/A |
| ihSTATUS_INVALID_TAGNAME_DELETEDTAG = -35 | N/A |
| ihSTATUS_INVALID_DHS_NODENAME = -36 | N/A |
| ihSTATUS_DHS_SERVICE_IN_USE = -37 | N/A |
| ihSTATUS_DHS_STORAGE_IN_USE = -38 | N/A |
| ihSTATUS_DHS_TOO_MANY_NODES_IN_MIRROR = -39 | N/A |
| ihSTATUS_ARCHIVE_IN_SYNC = -40 | N/A |
| InvalidArchiveName= -41 | N/A |
| InvalidSession = 1 | Session id is invalid. |
| SessionExpired = 2 | Session has expired. |
| UnknownError = 3 | Unknown error, please check server log. |
| NoValidClientBufferManager= 4 | No valid client buffer manager. |
| NoValueInDataSet = 5 | No value in returned data set. |
| TagNotExisting = 6 | Tag doesn't exist. |
| ClientBufferManagerCommunicationError = 7 | Service call to central buffer server fail. |
| TagTypeNotSupported=8 | Tag type is not supported. |
| ValueTypeNotMatchTagDataType = 9 | Value type doesn't match tag data type. |
| InvalidParameter=10 | Invalid query parameter. |
| TagSearchResultIsHuge = 11 | Tag Search Criteria result was more than 5000. |
| InvalidHistorianServer=12 | No valid server or historian server name isn't in the server list. |