Figure 8 shows the SercosParameterType. The SercosParameterType is a subtype of BaseDataVariableType (defined in OPC UA specification OPC 10000-5) and represents Sercos Parameters.

Figure 8 – Sercos ParameterType

All the SercosParameterType instances of each device are referenced as component from the ParameterSet Object (BaseObjectType) (defined in OPC UA specification for devices).

Every Sercos Parameter consists of elements. Elements are used to supply all information about the Sercos Parameter. The value of the parameter is transformed according to the DataType transformation rules (defined in 4.3.3). The attribute element contains e.g. read and write access rights and is mapped to the OPC UA attributes (for more information see Sercos Generic Device Profile specification).

SercosParameterType is formally defined in Table 9.

Table 9 – SercosParameterType Definition

Attribute	Value
BrowseName	SercosParameterType
IsAbstract	False
ValueRank	-2 (-2 = any)
DataType	BaseDataType
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the BaseDataVariableType defined in OPC UA specification OPC 10000-5.
HasProperty	Variable	Attribute	UInt32	PropertyType	Mandatory
HasProperty	Variable	DisplayValue	String	PropertyType	Mandatory
HasProperty	Variable	DisplayMaxValue	String	PropertyType	Optional
HasProperty	Variable	DisplayMinValue	String	PropertyType	Optional
HasProperty	Variable	Exponent	SByte	PropertyType	Optional
HasProperty	Variable	MaxValue	BaseDataType	PropertyType	Optional
HasProperty	Variable	MinValue	BaseDataType	PropertyType	Optional
HasProperty	Variable	ProcedureCommand	Boolean	PropertyType	Optional

Attribute (OPC UA Property) represents the Sercos Parameter element Attribute, which contains bit-coded data. Parts of this element are mapped to individual elements as following:

• Write Protection is mapped to the OPC UA attribute AccessLevel.
• Decimal Point is mapped to the Exponent variable.
• Display Format is mapped to the DisplayValue variable.
• Procedure Command is mapped to the ProcedureCommand variable.
• DataType and DataLength are mapped to the OPC UA attributes DataType.

DisplayValue represents the converted Sercos Parameter value as an ASCII String. Decimal seperator is formatted with respect to the given “locale” (“locale” is a set of parameters that defines the user's language, country and any special variant preferences).

DisplayMaxValue and DisplayMinValue converts the value of MaxValue and MinValue to String respectively.

Exponent is the optional scaling element of each parameters value (operational data) which applies on DisplayValue. For instance, Exponent of 1E-4 is -4 for both signed and unsigned decimal data types.

MaxValue is the largest numerical value for the parameter, which can be processed by the Sercos device. When, in a write request for the parameter, the MaxValue is exceeded, the value of the parameter is not changed and related OPC UA StatusCode will be returned. The source of MaxValue is the Sercos element Maximum Value of the parameter.

MinValue is the smallest numerical value for the parameter, which can be processed by the Sercos device. When, in a write request for the parameter, the MinValue is exceeded, the value of the parameter is not changed and related OPC UA StatusCode will be returned. The source of MinValue is the Sercos element Minimum Value of the parameter.

ProcedureCommand Variable shows whether the parameter is a Sercos procedure command (=true) or not (= false).

The Sercos Parameter Names are corresponding to the IDN notation, e.g. “S-0-1301-0.1”.

Sercos Procedure Commands are accessible as OPC UA Methods. These shall be referenced by the “MethodSet” object. Figure 9 shows an example model with Sercos Procedure Command Methods.

Figure 9 – Example model with Sercos Procedure Command Methods

The Method BrowseName and DisplayName contain the IDN as String, e.g. “P-0-0014”. The invocation of the Sercos Procedure Command Method causes the execution within the Sercos device.