WriteItem Method

Description

Writes separately given value, timestamp and quality into a named item using individual parameters specifying its location, and a specific data type.

DISPID (Dispatch ID):

For more information, see WriteItem in .NET Reference.

Syntax

Visual Basic
Public Sub WriteItem( _ ByVal machineName As String, _ ByVal serverClass As String, _ ByVal itemId As String, _ ByVal value As Variant, _ ByVal timestamp As Date, _ ByVal quality As DAQualities _ )

Visual Basic

Public Sub WriteItem( _
   ByVal machineName As String, _
   ByVal serverClass As String, _
   ByVal itemId As String, _
   ByVal value As Variant, _
   ByVal timestamp As Date, _
   ByVal quality As DAQualities _
)

Parameters

machineName

serverClass

itemId

value

timestamp

quality

Value	Description
DAQualities_BadNonspecific	Non-specific. Substatus for BAD Quality: The value is bad but no specific reason is known.
DAQualities_CommFailure	Comm Failure. Substatus for BAD Quality: Communications have failed. There is no last known value is available.
DAQualities_ConfigError	Configuration Error. Substatus for BAD Quality: There is some server specific problem with the configuration. For example the item in question has been deleted from the configuration.
DAQualities_DeviceFailure	Device Failure. Substatus for BAD Quality: A device failure has been detected.
DAQualities_EguExceeded	Engineering Units Exceeded. Substatus for UNCERTAIN Quality: The returned value is outside the limits defined for this parameter. Remark: In this case (per the Fieldbus Specification) the ‘Limits’ field indicates which limit has been exceeded but does NOT necessarily imply that the value cannot move farther out of range.
DAQualities_GoodNonspecific	Non-specific. Substatus for GOOD Quality: The value is good. There are no special conditions.
DAQualities_LastKnown	Last Known Value. Substatus for BAD Quality: Communications have failed. However, the last known value is available. Remark: The ‘age’ of the value may be determined from the TIMESTAMP in the OPCITEMSTATE.
DAQualities_LastUsable	Last Usable Value. Substatus for UNCERTAIN Quality: Whatever was writing this value has stopped doing so. The returned value should be regarded as ‘stale’. Remark: This differs from a BAD value with Substatus 5 (Last Known Value). That status is associated specifically with a detectable communications error on a ‘fetched’ value. This error is associated with the failure of some external source to ‘put’ something into the value within an acceptable period of time. Remark: The ‘age’ of the value can be determined from the TIMESTAMP in OPCITEMSTATE.
DAQualities_LocalOverride	Local Override. Substatus for GOOD Quality: The value has been Overridden. Typically this is means the input has been disconnected and a manually entered value has been ‘forced’.
DAQualities_NotConnected	Not Connected. Substatus for BAD Quality: The input is required to be logically connected to something but is not. This quality may reflect that no value is available at this time, for reasons like the value may have not been provided by the data source.
DAQualities_OutOfService	Out of Service. Substatus for BAD Quality: The block is off scan or otherwise locked. This quality is also used when the active state of the item or the group containing the item is InActive.
DAQualities_SensorCal	Sensor Not Accurate. Substatus for UNCERTAIN Quality: Either the value has ‘pegged’ at one of the sensor limits (in which case the limit field should be set to 1 or 2) or the sensor is otherwise known to be out of calibration via some form of internal diagnostics (in which case the limit field should be 0).
DAQualities_SensorFailure	Sensor Failure. Substatus for BAD Quality: A sensor failure had been detected (the ’Limits’ field can provide additional diagnostic information in some situations).
DAQualities_Subnormal	Sub-Normal. Substatus for UNCERTAIN Quality: The value is derived from multiple sources and has less than the required number of Good sources.
DAQualities_UncertainNonspecific	Non-specific. Substatus for UNCERTAIN Quality: There is no specific reason why the value is uncertain.
DAQualities_WaitingForInitialData	Waiting for Initial Data. Substatus for BAD Quality: After Items are added to a group, it may take some time for the server to actually obtain values for these items. In such cases the client might perform a read (from cache), or establish a ConnectionPoint based subscription and/or execute a Refresh on such a subscription before the values are available. This substatus is only available from OPC DA 3.0 or newer servers.

Return Type

See WriteItem in .NET Reference.

Remarks

For remarks, see WriteItem in .NET Reference.

Example

For examples, see WriteItem in .NET Reference.