The OPC UA for PROFINET Remote IO Information Model aims to offer Clients Objects and Services based on two RIO application profiles: Remote IO for Factory Automation (see [RIO FA]) and Remote IO for Process Automation (see [RIO PA]).

OPC UA for PROFINET Remote IO consists of all Objects and types provided by an OPC UA Server allowing OPC UA Clients to access the IO data of PN Submodules. The Information Model is divided into a PROFINET aspect offering detailed Telegram information and a functional aspect modelling Process Values as part of RIO Channel Objects. The two aspects offer different access paths for Clients and are connected by dedicated References to allow navigating to the preferred representation from either aspect.

The “RIOChannel” Object in the functional aspect aggregates Process Value Objects optionally offering additional information like Process Value qualifiers associated with the IO data. Figure 8 shows the basic channel model for an analog RIO Input Channel according to RIOforPA.

Figure 8 – Analog Input Channel Model in Functional Aspect with RIOforPA

The functional aspect with RIO of the Information Model contains as many RIO Channel objects as needed to represent the IO’s associated with the PN Submodules of the Device.

The “ProcessValue” Variable in Figure 8 contains an analog Process Value. The VariableType used to represent analog Process Values is RioPaAnalogProcessValueVariableType, the data type used by this VariableType is RioPaAnalogProcessValueDataType.

Configuration properties of the RIO Channel are provided with the “Config” Variable. There are individual configuration VariableTypes defined for each channel type, the type used for analog Input Channels according to RIOforPA is RioPaAnalogInputConfigVariableType.

Figure 9 shows all RIO Channel ObjectTypes, Process Value VariableTypes and configuration ObjectTypes which are defined in this specification to cover digital and analog Input and Output for RIOforPA and RIOforFA.

Figure 9 – RioChannel ObjectTypes

The RIO Channel ObjectTypes provide additional components, Variables and configuration Properties available for access by the Client which substantially differ between the various types, see sections 7.2 and 9.4 for details.

Figure 10 shows the Cyclic IO Telegram model accessible from the PN Submodule in the PROFINET aspect of the Information Model. If provided by the Server, the Telegram Object associated with one PN Submodule aggregates the Input and the Output Telegram Objects. The individual data points or variables within a Telegram are represented by Signal Objects. The Input Telegram and Output Telegram Objects aggregate the Signal Objects and provide additional information like provider status and consumer status.

Figure 10 – PROFINET Telegram Model

The Offset Property of the PnIoSignalType Object contains the position as byte offset of the signal from the start of the binary telegram.

The 0:RepresentsSameEntityAs Reference connects PnIoSignalType Objects with the “ProcessValue” Variables containing the Process Value provided by RIO Channel Objects in the functional aspect of the Information Model.

Figure 11 – 2 analog RIOforPA channels

Figure 11 shows the Channel model for analog Input according to RIOforPA to illustrate the relationship between the different aspects. The Process Values and their qualifiers are transmitted consecutively and are available for the user program in the Input section of the Process Image.

The connection of the PROFINET aspect and the functional aspect with two analog RIO Input Channels according to RIOforPA in the Information Model is shown in Figure 12.

Figure 12 – 2 analog RIOforPA Channels connected with Cyclic IO Telegram Model

The PnIoSignalType Objects “01_AI_1_Value” and “03_AI_2_Value” representing the Process Values in the PnIoTelegramType Object “Input” connect to the “ProcessValue” Variables which are components of the Input Channels “AI_1” and “AI_2” using a 0:RepresentsSameEntityAs Reference.

The PnIoSignalType Objects “02_AI_1_Q” and “04_AI_2_Q” representing the Process Value Qualifiers transmitted alongside the Process Values they belong to connect to the “QualifierValue” Variables also using a 0:RepresentsSameEntityAs Reference.

The direct connection of Signal Objects representing status data and qualifier Variables using 0:RepresentsSameEntityAs References in the way shown in Figure 12 is only possible for analog Input and analog Output according to RIOforPA, since only analog RIOforPA transmits the status data (= qualifiers) alongside to each Process Value as separate Signal in the Telegram.

Digital RIOforPA Input and Output Channels transmit value and status packed into one byte (see [RIO PA] sec. 7.3.1.2 “Discrete Values”). Figure 13 shows the digital Output Channel model according to RIOforPA.

Figure 13 – RIOforPA digital Output Channel Model

No separate qualifier Signal Objects and no 0:RepresentsSameEntityAs References to qualifier Variables exist for digital RIOforPA values, as shown in Figure 14.

Figure 14 – 2 digital RIOforPA Channels connected with Cyclic IO Telegram Model

The qualifiers in RIOforFA Channels are single bits transferred together in one or more bytes (see [RIO FA] sec. 7.2). Therefore, the Telegram contains an arbitrary number of qualifier bits distributed among several continuous bytes.

Figure 15 – FA Channel Group

Figure 15 shows the analog Output Channel model and a Channel Group according to RIOforFA. The qualifiers of the Output Process Values are transferred as single bits packed into one byte in the Input section of the process image.

Figure 16 shows the References from Signal Objects in the PROFINET aspect to their counterparts in the RIO aspect for analog RIO Output Channels according to RIOforFA. The qualifier Signal Object is connected to a RioBitFieldVariableType Variable containing a bit field. The bit field and the RIO Channel Objects are related using RIO Channel Group Objects.

The Output Signal Objects “01_AO_1_Value” and “02_AO_2_Value” are connected to the Process Value Variables with 0:RepresentsSameEntityAs References in the same way as described before.

The qualifiers of RIO Output Channels according to RIOforFA are transmitted separated from the values in an Input Signal since qualifiers of RIOforFA Output Channels are provided by the Channel and are part of the Input section of the process image. Therefore, the qualifier Signal Object “03_AO_1-AO_2_Q” containing the status information for both Output Channels is a component of the Input Signal Variable and relates to the “OutputImageQualifiers” Variable in the functional aspect of the Information Model using a 0:RepresentsSameEntityAs Reference.

The “SM1” PROFINET submodule Object connects to the RioFaAnalogChannelGroupType Object using a 0:RepresentsSameFunctionalityAs Reference. Since the RIO Channel Group types allow aggregating of Input and Output but are separated into different types for digital and analog IO, hybrid digital/analog submodules may reference a digital Channel Group type object and an analog Channel Group type object with 0:RepresentsSameFunctionalityAs References.

For analog RIOforFA Input Channels, the RIO Channel Group modelling is done in the same way as shown in Figure 16, but all Signal Objects are components of the Input Signal Variable.

Figure 16 – 2 analog RIOforFA Output Channels

The mapping of the bit number inside the RioBitFieldVariableType Variable to the RIO Channel the status bit belongs to is done in the following way: The Value of the RioChannelNumber Property of each Channel Object corresponds to the bit number of the status bit inside the bit field.

The Server may optionally provide additional RioFaProcessValueQualifierVariableType Variables as components of the Process Value Variables to make the status information directly accessible for Clients without decoding the value structure of the Process Value Variable.

Figure 17 – RIOforFA Digital Input Channel Model

Digital RIO Channels according to RIOforFA transmit the Process Values as single bits packed together into one or more bytes. One Telegram contains an arbitrary number of value bits which belong to separate RIO Channels distributed among continuous bytes, as shown in Figure 17.

Figure 18 shows the modelling of a digital RIOforFA Input Channel Group. The RIO Channel Group Object aggregates the value and status information for 32 digital RIOforFA Input Channels. The RioBitFieldVariableType Variable “ InputImage” is a bit field representing the digital values of 32 Process Values. The “InputImageQualifier” Variable of the same type contains the status bits.

The optional “InputChannel” Objects may contain single RioFaDigitalInputChannelType Objects providing detailed information for each aggregated RIO Channel. The “01_DI_1-DI_32_Value” Object is connected to a RioBitFieldVariableType Variable containing a bit field which represents the digital values for more than one RIO Channel. The qualifier Signal Object is also connected with a bit field Variable containing the status bits.

Figure 18 – RIO FA Digital Input Channel Group

Figure 19 shows the modelling of a digital RIOforFA Output Channel Group. The “OutputImageQualifier” bit field Variable is connected to the qualifier Signal Object which is a component of the Input Telegram.

Figure 19 – RIO FA Digital Output Channel Group

Figure 20 shows an analog RIO Channel Group aggregating two RioPaAnalogInputChannelType Objects. The “InputValues” Variable containing an array of RioPaAnalogValueDataType structures is connected to the “Input” Telegram Variable in the PROFINET aspect using a 0:RepresentsSameEntityAs Reference.

Figure 20 – RIOforPA Analog Input Channel Group

Figure 21 shows a digital RIO Channel Group aggregating two RioPaDigitalOutputChannelType Objects. The “OutputImage” Variable containing an array of RioPaDigitalValueDataType structures is connected with the “Output” Telegram Variable in the PROFINET aspect using a 0:RepresentsSameEntityAs Reference.

Figure 21 – RIOforPA Digital Output Channel Group

For RIO Channel Group Objects the following rules apply to Servers.

RIOforFA:RIO Channel Group Objects shall be provided always if the Cyclic IO Telegram model is provided by the Server. RIO Channel Groups could be used for lightweight modelling of digital multichannel I/O submodules when the RIO Channel Objects are omitted and only the I/O image Variables are used.

RIOforPA:RIO Channel Group Objects could be used if logical grouping of channels shall be done for asset relations on the RIO aspect side if the PROFINET aspect is omitted.

General:Servers may always provide RIO Channel Group Objects, independent from the conditions mentioned above.

Servers shall allow Method invocation and write access to Variables only for Sessions using dedicated user accounts. There shall exist user accounts with restricted rights (that is, no Method invocation and read-only access to Variables) for Clients performing data acquisition or diagnosis also.

If well-known Roles are supported by the Server, role-based security shall be applied. Method invocation as well as write access shall only be possible if the well-known “Operator” Role is granted to the Client’s Session.

When returning the Value of Process Values, the Server shall set the StatusCode member of the DataValue structures returned by the Read Service and the Publish Service consistent with the Process Value Qualifier information defined for Process Value Variables and structures.

RIOforPA status information is conveyed to the Client as copy of the original status transmitted in the telegram signal. The value of the RioPaProcessValueQualifierVariableType Variable and the Qualifier member of the RioPaAnalogValueDataType and the RioPaDigitalValueDataType shall contain the original status. In addition to this, the status can be encoded into additional qualifier values encoded as RioQualityEnumeration, RioSpecifierEnumeration and RioQualifierEnumeration enumeration values.

If the Device generates condensed status codes restricted to NE 107 (See [PCD] chapter 5.4.3.2), the status information delivered for one Process Value and the OPC UA StatusCode shall be set consistent as defined in Table 13.

Table 13 – Condensed status restricted to NE 107

NE 107	Status Byte Values	Description according to Profile		OPC UA Status Code	RioQualityEnumeration	RioSpecifierEnumeration	RioQualifierEnumeration
Failure (F)	0x24,0x26		BAD - maintenance alarm, more diagnosis available	Bad, 0x80000000	BAD	FAILURE	BAD_MAINTENANCE_ALARM
	0x25, 0x27						BAD_MAINTENANCE_ALARM_SIMULATION_ACTIVE
Check(C)	0x3C, 0x3E		BAD - function check / local override	Bad, 0x80000000	BAD	FUNCTION_CHECK	BAD_FUNCTION_CHECK
	0x3D, 0x3F						BAD_FUNCTION_CHECK_SIMULATION_ACTIVE
Out of Specification (S)	0x78, 0x7A		UNCERTAIN - process related, no maintenance	Uncertain, 0x40000000	UNCERTAIN	OUT_OF_SPECIFICATION	UNCERTAIN_NO_MAINTENANCE
	0x79, 0x7B						UNCERTAIN_NO_MAINTENANCE_SIMULATION_ACTIVE
Maintenance (M)	0xA4, 0xA6		GOOD - maintenance required	Good, 0x00000000	GOOD	MAINTENANCE_REQUEST	GOOD_MAINTENANCE_REQUIRED
	0xA5, 0xA7						GOOD_MAINTENANCE_REQUIRED_SIMULATION_ACTIVE
	0xA8, 0xAA		GOOD - maintenance demanded	Good, 0x00000000	GOOD	MAINTENANCE_REQUEST	GOOD_MAINTENANCE_DEMANDED
	0xA9, 0xAB						GOOD_MAINTENANCE_DEMANDED_SIMULATION_ACTIVE
Good (G)	0x80		GOOD - ok	Good, 0x00000000	GOOD	NORMAL	GOOD
Check (C)	0x81		GOOD - simulation active	GoodEdited, 0x00DC0000	GOOD	FUNCTION_CHECK	GOOD_SIMULATION_ACTIVE
Good (G)	0x82		GOOD - update event	Good, 0x00000000	GOOD	NORMAL	UPDATE

The two values for status bytes consider the possible appearance of the update bit as defined in [PCD]. The update bit is not mapped further into separate status values. In contrast, the appearance of the “simulation active” bit is mapped to special values of the RioQualifierEnumeration.

If the Server generates status codes with detailed information (See [PCD] chapter 5.4.3.3), the status information delivered for one Process Value and the OPC UA StatusCode shall be set consistent as defined in Table 14.

Table 14 – Condensed status with detailed information

NE 107	Status Byte Range	Description according to Profile	OPC UA Status Code	RioQualityEnumeration	RioSpecifierEnumeration	RioQualifierEnumeration
Failure (F)	0x00	BAD - non specific	Bad, 0x80000000	BAD	FAILURE	BAD_NON_SPECIFIC
Failure (F)	0x08, 0x0A	BAD - not connected	BadNotConnected, 0x808A0000	BAD	FAILURE	BAD_NOT_CONNECTED
	0x09, 0x0B					BAD_NOT_CONNECTED_ SIMULATION_ACTIVE
Failure (F)	0x20, 0x22	BAD - passivated	BadOutOfService, 0x808D0000	BAD	FAILURE	BAD_PASSIVATED
	0x21, 0x23					BAD_PASSIVATED_SIMULATION_ACTIVE
Failure (F)	0x24, 0x26	BAD - maintenance alarm, more diagnosis available	Bad, 0x80000000	BAD	FAILURE	BAD_MAINTENANCE_ALARM
	0x25, 0x27					BAD_MAINTENANCE_ALARM_ SIMULATION_ACTIVE
Failure (F)	0x28, 0x2A	BAD - process related, no maintenance	Bad, 0x80000000	BAD	FAILURE	BAD_PROCESS
	0x29, 0x2B					BAD_PROCESS_SIMULATION_ACTIVE
Check(C)	0x3C, 0x3E	BAD - function check / local override	Bad, 0x80000000	BAD	FUNCTION_CHECK	BAD_FUNCTION_CHECK
	0x3D, 0x3F					BAD_FUNCTION_CHECK_ SIMULATION_ACTIVE
Failure (F)	0x48, 0x4A	UNCERTAIN - substitute set	UncertainSubstituteValue, 0x40910000	UNCERTAIN	FAILURE	UNCERTAIN_SUBSTITUTE_SET
	0x49, 0x4B					UNCERTAIN_SUBSTITUTE_SET_ SIMULATION_ACTIVE
Check (C)	0x4C, 0x4E	UNCERTAIN - initial value	UncertainInitialValue, 0x40920000	UNCERTAIN	FUNCTION_CHECK	UNCERTAIN_INITIAL_VALUE
	0x4D, 0x4F					UNCERTAIN_INITIAL_VALUE_ SIMULATION_ACTIVE
Maintenance (M)	0x68, 0x6A	UNCERTAIN - maintenance demanded	Uncertain, 0x40000000	UNCERTAIN	MAINTENANCE_REQUEST	UNCERTAIN_MAINTENANCE_ DEMANDED
	0x69, 0x6B					UNCERTAIN_MAINTENANCE_ DEMANDED_SIMULATION_ACTIVE
Out of Specification (S)	0x78, 0x7A	UNCERTAIN - process related, no maintenance	Uncertain, 0x40000000	UNCERTAIN	OUT_OF_SPECIFICATION	UNCERTAIN_NO_MAINTENANCE
	0x79, 0x7B					UNCERTAIN_NO_MAINTENANCE_ SIMULATION_ACTIVE
Good (G)	0x80, 0x82	GOOD	Good, 0x00000000	GOOD	NORMAL	GOOD
	0x81, 0x83					GOOD_SIMULATION_ACTIVE
Good (G)	0xA0	GOOD - initiate fail safe	GoodInitiateFault State, 0x04080000	GOOD	NORMAL	GOOD_INITIATE_FAULT_STATE
Maintenance (M)	0xA4, 0xA6	GOOD - maintenance required	Good, 0x00000000	GOOD	MAINTENANCE_REQUEST	GOOD_MAINTENANCE_REQUIRED
	0xA5, 0xA7					GOOD_MAINTENANCE_REQUIRED_ SIMULATION_ACTIVE
	0xA8, 0xAA	GOOD - maintenance demanded	Good, 0x00000000	GOOD	MAINTENANCE_REQUEST	GOOD_MAINTENANCE_DEMANDED
	0xA9, 0xAB					GOOD_MAINTENANCE_DEMANDED_ SIMULATION_ACTIVE
Good (G)	0x9C, 0x9E	GOOD - local override	GoodLocalOverride, 0x00960000	GOOD	NORMAL	GOOD_LOCAL_OVERRIDE
	0x9D, 0x9F					GOOD_LOCAL_OVERRIDE_ SIMULATION_ACTIVE
Good (G)	0xBC, 0xBE	GOOD - function check	Good, 0x00000000	GOOD	NORMAL	GOOD_FUNCTION_CHECK
	0xBD, 0xBF					GOOD_FUNCTION_CHECK_ SIMULATION_ACTIVE

For Devices generating classic status codes, OPC UA Servers shall set the status information delivered for one Process Value and the OPC UA StatusCode consistent as defined in Table 15.

Table 15 – Classic status codes

Sub-status	Description	OPC UA Status Code	Status Byte	RioQualityEnumeration	RioSpecifier Enumeration UNSPECIFIED	RioQualifierEnumeration
Quality BAD
0	non-specific	Bad, 0x80000000	0x00.. 0x03	BAD		BAD_NOT_SPECIFIC
1	configuration error	BadConfigurationError, 0x80890000	0x04.. 0x07			BAD_NOT_SPECIFIC
2	not connected	BadNotConnected, 0x808A0000	0x08.. 0x0B			BAD_NOT_CONNECTED
3	device failure	BadDeviceFailure, 0x808B0000	0x0C.. 0x0F			BAD_NOT_SPECIFIC
4	sensor failure	BadSensorFailure, 0x808C0000	0x10.. 0x13			BAD_NOT_SPECIFIC
5	no communication (LUV)	BadCommunicationError, 0x80050000	0x14.. 0x17			BAD_NOT_SPECIFIC
6	no communication (no LUV)	BadNoCommunication, 0x80310000	0x18.. 0x1B			BAD_NOT_SPECIFIC
7	out of service	BadOutOfService, 0x808D0000	0x1C.. 0x1F			BAD_PASSIVATED
Quality UNCERTAIN
0	non specific	Uncertain, 0x40000000	0x40.. 0x43	UNCERTAIN		UNCERTAIN_NO_ MAINTENANCE
1	last usable value (LUV)	UncertainLastUsableValue, 0x40900000	0x44.. 0x47			UNCERTAIN_NO_ MAINTENANCE
2	substitute value	UncertainSubstituteValue, 0x40910000	0x48.. 0x4B			UNCERTAIN_SUBSTITUTE_SET
3	initial value	UncertainInitialValue, 0x40920000	0x4C.. 0x4F			UNCERTAIN_INITIAL_VALUE
4	sensor conversion not accurate	UncertainSensorNotAccurate, 0x40930000	0x50.. 0x53			UNCERTAIN_NO_ MAINTENANCE
5	engineering unit violation	UncertainEngineeringUnits Exceeded, 0x40940000	0x54.. 0x57			UNCERTAIN_NO_ MAINTENANCE
6	sub normal	UncertainSubNormal, 0x40950000	0x58.. 0x5B			UNCERTAIN_NO_ MAINTENANCE
7	configuration error	UncertainConfigurationError, 0x420F0000	0x5C.. 0x5F			UNCERTAIN_NO_ MAINTENANCE
8	simulated value	UncertainSimulatedValue, 0x42090000	0x60.. 0x63			UNCERTAIN_NO_ MAINTENANCE_SIMULATION_ACTIVE
9	sensor calibration	UncertainSensorCalibration, 0x420A0000	0x64.. 0x67			UNCERTAIN_NO_ MAINTENANCE
Quality GOOD (Non Cascade)
0	ok	Good, 0x00000000	0x80.. 0x83	GOOD		GOOD
1	update event	Good, 0x00000000	0x84.. 0x87			GOOD
2	active advisory alarm	GoodFaultStateActive, 0x04070000	0x88.. 0x8B			GOOD
3	active critical alarm	GoodFaultStateActive, 0x04070000	0x8C.. 0x8F			GOOD
4	unacknowledged update event	Good, 0x00000000	0x90.. 0x93			GOOD
5	unacknowledged advisory alarm	GoodFaultStateActive, 0x04070000	0x94.. 0x97			GOOD
6	unacknowledged critical alarm	GoodFaultStateActive, 0x04070000	0x98.. 0x9B			GOOD
7	reserved	-
8	initiate fail safe	GoodInitiateFaultState, 0x04080000	0xA0	GOOD		GOOD_INITIATE_ FAULT_STATE
9	maintenance required	Good, 0x00000000	0xA4.. 0xA7			GOOD_MAINTENANCE_ REQUIRED
Quality GOOD (Cascade)
0	ok	GoodCascade, 0x04090000	0xC0.. 0xC3	GOOD		GOOD
1	initialization acknowledged	GoodCascadeInitializationAcknowledged, 0x04010000	0xC4.. 0xC7			GOOD
2	initialization request	GoodCascadeInitializationRequest, 0x04020000	0xC8.. 0xCB			GOOD
3	not invited	GoodCascadeNotInvited, 0x04030000	0xCC.. 0xCF			GOOD
4	reserved	-
5	do not select	GoodCascadeNotSelected, 0x04040000	0xD4.. 0xD7	GOOD		GOOD
6	local override	GoodLocalOverride, 0x00960000	0xD8.. 0xDB			GOOD_LOCAL_OVERRIDE
7	reserved	-		-
8	initial fail safe	GoodInitiateFaultState, 0x04080000	0xE0	GOOD		GOOD_INITIATE_ FAULT_STATE

According to [PCD PB] chapter 5.3.4.2.1, the classic status codes shall be supported for legacy Devices requiring backward compatibility only. Otherwise, only condensed status generation or condensed status with detailed information as defined in 6.8.1.1 and 6.8.1.2 is required.

RIOforFA status information is conveyed to the Client as copy of the original status transmitted in the telegram signal. The value of the RioFaProcessValueQualifierVariableType Variable and the Qualifier member of the RioFaAnalogValueDataType and the RioFaDigitalValueDataType shall contain the original status. In addition to this, the status can be encoded into additional qualifier values encoded as RioQualityEnumeration.

The status information delivered for one Process Value and the OPC UA StatusCode shall be set consistent as defined in Table 16.

Table 16 – RIOforFA StatusCodes

Status Bit Value	Description according to Profile (See [RIO FA] chapter 7.1)	OPC UA Status Code	RioQualityEnumeration
1 (good)	Input: Process Value can be used by host application. Output: Physical signal equals Process Value.	Good, 0x00000000	GOOD
0 (bad)	Input: Process Value should not be used by host application. Output: Substitute Value applied by (Sub)Module.	Bad, 0x80000000	BAD

When returning arrays of Process Values, the Server shall set the Severity of the StatusCode to “Bad” if one or more Process Values in the returned array are “Bad”. If no Process Value in the array is “Bad”, the Severity returned shall be “Uncertain” if one or more Process Values in the returned array are “Uncertain”. The Severity returned shall be “Good” only if all Process Values in the array are “Good”.