Ethernet POWERLINKMultiple PReq/PResEPSG DS 302-D V1.1.1

EPSG Draft Standard 302-D

Ethernet POWERLINKPart D: Multiple PReq/PRes

Version 1.1.1©

B&R(B&R Industrial Automation GmbH)
2023

EPSG DS 302-D V1.1.1-2-

B&R Industrial Automation GmbH

POWERLINK-Office
B&R Straße 15142 Eggelsberg
Austria

powerlink.office@br-automation.com
www.br-automation.com/en/technologies/powerlink/

The EPSG Draft Standard 302-D “Ethernet Powerlink, Part D: Multiple PReq/PRes” has been provided
by Ethernet POWERLINK Standardisation Group (hereinafter referred to as “EPSG”). As a consequenceof the EPSG being dissolved from March 31st, 2023, B&R Industrial Automation GmbH will – as theformal successor of EPSG regarding the rights and content – make the Ethernet Powerlink Part D:
Multiple PReq/PRes available as open source on it’s own website subject to the conditions mentioned
in the disclaimer under clause Pre. 1 of this document. B&R Industrial Automation GmbH especiallydisclaims liability for any personal injury, property or other damage, of any nature whatsoever, whether
special, indirect, consequential, or compensatory, directly or indirectly resulting from the publication, useof, or reliance upon this, or any other EPSG Standard document.

EPSG DS 302-D V1.1.1

Pre. 1-3-Disclaimer

Use of this EPSG Standard is wholly voluntary. The EPSG disclaims liability for any personal injury,
property or other damage, of any nature whatsoever, whether special, indirect, consequential, orcompensatory, directly or indirectly resulting from the publication, use of, or reliance upon this, or any
other EPSG Standard document.
The EPSG does not warrant or represent the accuracy or content of the material contained herein, andexpressly disclaims any express or implied warranty, including any implied warranty of merchantabilityor fitness for a specific purpose, or that the use of the material contained herein is free from patent
infringement. EPSG Standards documents are supplied “AS IS”.
The existence of an EPSG Standard does not imply that there are no other ways to produce, test,measure, purchase, market, or provide other goods and services related to the scope of the EPSG
Standard. Furthermore, the viewpoint expressed at the time a standard is approved and issued is subject
to change brought about through developments in the state of the art and comments received fromusers of the standard. Users are cautioned to check to determine that they have the latest edition of any
EPSG Standard.
In publishing and making this document available, the EPSG is not suggesting or rendering professionalor other services for, or on behalf of, any person or entity. Nor is the EPSG undertaking to perform any
duty owed by any other person or entity to another. Any person utilizing this, and any other EPSG
Standards document, should rely upon the advice of a competent professional in determining theexercise of reasonable care in any given circumstances.
Interpretations: Occasionally questions may arise regarding the meaning of portions of standards as
they relate to specific applications. When the need for interpretations is brought to the attention of theEPSG, the group will initiate action to prepare appropriate responses. Since EPSG Standards represent
a consensus of concerned interests, it is important to ensure that any interpretation has also received
the concurrence of a balance of interests. For this reason, the EPSG and its members are not able toprovide an instant response to interpretation requests except in those cases where the matter has
previously received formal consideration.
Comments for revision of EPSG Standards are welcome from any interested party, regardless ofmembership affiliation with the EPSG. Suggestions for changes in documents should be in the form ofa proposed change of text, together with appropriate supporting comments. Comments on standards
and requests for interpretations should be sent to the address given on the page before.

Pre. 1.1

Patent noticeAttention is called to the possibility that implementation of this standard may require use of subject
matter covered by patent rights. By publication of this standard, no position is taken with respect to theexistence or validity of any patent rights in connection therewith. B&R shall not be responsible for
identifying patents for which a license may be required by an EPSG standard or for conducting inquiries
into the legal validity or scope of those patents that are brought to its attention.

EPSG DS 302-D V1.1.1

Pre. 2-4-

History

Vers.
0.0.1
0.0.2

Date
2009-06-10
2009-06-25

AuthorStephan Kirchmayer
Stephan Kirchmayer

B&R
B&R

0.0.3
0.0.4
0.1.0
1.0.0

2009-09-04
2009-10-13
2013-03-29
2013-12-18

Stephan Kirchmayer
Stephan Kirchmayer
Stephan Kirchmayer
Stephan Kirchmayer

B&R
B&R
B&R
B&R

1.0.1
1.0.2
1.1.0
1.1.1

2018-03-14
2019-01-08
2019-04-08
2023-05-31

Stephan Kirchmayer
Stephan Kirchmayer
Stephan Kirchmayer
Stephan Kirchmayer

B&R
B&R
B&R
B&R

short description
createdPDO_RxCommParam_XXh_REC,
PDO_TxCommParam_XXh_REC sub-index 3
Figure and additional object description added
Feedback from TWG meeting 9/2010
Minor layout changes, status changed to DSP
Minor layout changes, category changed for
D_DLL_MultiplePReqPRes_BOOL to M
status changed to DS
Feedback from TWG meeting 03/2018
Document status changed to DSPDocument status changed to DS© B&R due to dissolution of EPSGEPSG DS 302-D V1.1.1

Pre. 3Pre. 1Pre. 1.1
Pre. 2Pre. 3Pre. 4Pre. 5Pre. 6Pre. 6.1
Pre. 6.2
Pre. 71
1.1
1.22
2.1
2.2
2.3
2.4
2.5
3
4
56
6.1
6.2
6.3
6.4
6.5
App. 1-5-ContentDisclaimer
Patent noticeHistory
ContentTables
FiguresDefinitions and Abbreviations
Definitions
Abbreviations
References
Introduction
Overview
Summary of features
PDO configuration
Assignment of node IDs used in frames to real nodes
Rx mapping
Tx mapping
Multiplexing of a virtual node
Payload Limits
Special boot-up procedures
Error Handling
Mapping of more than 254 objects into one PDO
Additional object description
Object 1400h .. 14FFh: PDO_RxCommParam_XXh_Rec
Object 1800h .. 18FFh: PDO_TxCommParam_XXh_Rec
Object 1F81h: NMT_NodeAssignment_AU32
Object 1F82h: NMT_FeatureFlags_U32
Object 1F94h: NMT_PdoNodeAssign_AU8
Device Description Entries (normative)

334567888910101011111111111213141516161617171719

EPSG DS 302-D V1.1.1

Pre. 4
Tab. 1
Tab. 2
Tab. 3-6-Tables
RxMessageType_U8 value interpretation
NMT_NodeAssignment_AU32 additional bit interpretation
NMT_FeatureFlags_U32 additional bit interpretation

161717EPSG DS 302-D V1.1.1

Pre. 5
Fig. 1.

-7-Figures
Multiple PReq/PRes cycle overview

10EPSG DS 302-D V1.1.1-8-

Pre. 6Definitions and Abbreviations

Pre. 6.1

Definitions

Pre. 6.2

AbbreviationsEPSG DS 302-D V1.1.1

Pre. 7-9-References[1]
EPSG Draft Standard 301 (EPSG DS 301), Ethernet POWERLINK, Communication ProfileSpecificationEPSG DS 302-D V1.1.1-10-

Introduction

1

For a Controlled Node the existing POWERLINK specification restricts the amount of isochronous
payload data that can be sent to 1490 bytes.
The Managing Node may only send 1490 bytes in its PResMN frame additionally.
Conversely, this means that a node cannot receive more than 1490 bytes of isochronous data fromanother node. (except additional 1490 bytes from PResMN)
This extension is to overcome the limitation mentioned above.

1.1

Overview

The extension utilizes unused node numbers to be able to send more data to and from a node. These
node numbers are additionally assigned to Multi-PReq/PRes capable Controlled Nodes by theManaging Node.
A Multi-PReq/PRes capable node shall reply to such a PReq frame by a PRes with the dedicated virtual
node number.
The configuration is done via existing PDO mapping configuration and an additional object for assigning
the virtual node numbers to the real Controlled Nodes.

Fig. 1.

Multiple PReq/PRes cycle overview

For network management the Managing Node uses the regular node numbers only. The additional
virtual nodes are just for PDO mapping and sending and receiving PReq/PRes frames. An error on oneof these frames is handled like an error on the regular frame of the real existing node. The particularerror counters are only incremented ones whether a frame to/from the real or virtual node number orboth frames trigger an error handling.

1.2••••

Summary of features
Maximum of 252 PReq/PRes frames per cycle
Each Controlled Node may map more than 254 objects per PDO.
Crosstraffic from Multi-PReq/PRes nodes to conventional nodes and v.v. possible
Fully compatible with conventional Controlled Nodes

EPSG DS 302-D V1.1.1-11-2

PDO configuration

2.1

Assignment of node IDs used in frames to realnodes

A new object 1F94h NMT_PdoNodeAssign_AU8 is used to assign all used node IDs to the real node
IDs of the nodes present in the network.
The sub-index is the node ID indicated in the PReq/PRes frames and the value hold by this sub-index
is the real node ID.
See chapter 6.5 for object description.

2.2Rx mapping

The source (in PRes) resp. destination (in PReq) address of the Rx mapping is described by the objects
1400h .. 14FFh PDO_RxCommParam_XXh_REC.
By [1] the sub-index 1 holds the node ID. The value 0 is reserved for the PReq addressed to this node.
So far all other values indicate a PRes, i.e. on Controlled Nodes crosstraffic from other nodes. The subindex 2 gives the mapping version.
If there is more than one PReq frame addressed to a node, one is sent with the destination ID equal tothe node ID of the Controlled Node. All other PReq frames are sent with different node IDs.
On Controlled nodes a sub-index 3 shall be added to PDO_RxCommParam_XXh_REC holding themessage type of the receive frame. Sub-index 1 still holds the node ID but if sub-index 1 is not equal 0
this new sub-index 3 indicates, if the Rx frame is a PReq or a PRes frame.
Note: By this it is also possible to configure the receiving of the own PRes.
See 6.1 for object description
Alternatively a Controlled Node may check NMT_PdoNodeAssign_AU8 to be able to distinguishbetween a PReq and a PRes frame. The node ID indicated in PDO_RxCommParam_XXh_REC subindex 1 gives the sub-index of NMT_PdoNodeAssign_AU8. If the value of a sub-index ofNMT_PdoNodeAssign_AU8 is equal the own node ID, the frame is a PReq otherwise a PRes. If thevalue of PDO_RxCommParam_XXh_REC sub-index 1 is 0 the frame is a PReq as defined in [1].On aManaging Node the Rx mapping is as defined in [1].

2.3

Tx mapping

The source (in PRes, PResMN) resp. destination (in PReq) address of the Tx mapping is described bythe objects 1800h .. 18FFh PDO_TxCommParam_XXh_REC.
The sub-index 1 holds the node ID. In conventional POWERLINK networks [1] this value is not valid on
Controlled Nodes because there is only one TPDO. The sub-index 2 gives the mapping version.
With this extension sub-index 1 is also used on Controlled Nodes because more than one TPDO may
be mapped.
Now, on a Controlled Node sub-index 1 holds the source node ID of the TPDO. This may be the real
node ID or the virtual node ID depending on the configuration. If the value of the sub-index is 0 the own
node ID shall be used.
On the Managing Node sub-index 1 holds the destination node ID of the PReq resp. the source node
ID of the PResMN frame. It is the source node ID of the PResMN if the value of the dedicated sub-index
in the object 1F94h NMT_PdoNodeAssign_AU8 is the node number of the Managing Node (240).

2.4

Multiplexing of a virtual node

The Managing Node shall use the object 1F9Bh (NMT_MultiplCycleAssign_AU8) to assign a virtual
node to a multiplexed slot like it is done for real nodes.
If a real node is multiplexed also all of its assigned virtual nodes shall be multiplexed too and vice versa.
However the virtual PReq/PRes frames can be assigned to different multiplexed slots.

EPSG DS 302-D V1.1.1

2.5-12-Payload Limits

The Managing Node shall use the object 1F8Bh (NMT_PReqPayloadLimitList_AU16) to assign thePReq payload limit of a virtual node like it is done for real nodes.
The Managing Node shall use the object 1F8Dh (NMT_PresPayloadLimitList_AU16) to to assign thePRes payload limit of a virtual node like it is done for real nodes. A Controlled Node shall support theobject if it supports virtual node IDs.
The actual PReq and PRes frame sizes for virtual nodes shall be derived from the mapped data. 1F98h
sub-index 4 and 5 (PReq-/PResActPayloadLimit) shall be used for the PReq and PRes of the real nodeonly.

EPSG DS 302-D V1.1.1

3-13-

Special boot-up proceduresPReq/PRes
framesto/from
virtualnodes
shallbesentin
theNMTstates
NMT_CS_READY_TO_OPERATE and NMT_CS_OPERATIONAL of the CN only.
Note: Sending virtual PReq/PRes frames in NMT_CS_PRE_OPERATIONAL_2 may result in collisions,e.g. if a node with a stored configuration with virtual node IDs is plugged into a different network, it may
receive PReq frames to its virtual node IDs and respond with PRes frames because the configuration is
not yet updated. This may result in collisions with PRes frames from another real node with its node IDequal to a former virtual node ID.

EPSG DS 302-D V1.1.1

4-14-Error Handling

Loss of PReq resp. PRes theshold counting shall be done individual for each real and virtual node ID.
The threshold for virtual node IDs shall be the same as for the real node ID. The Loss of PReq resp.
PRes error handling shall be triggered if at least one individual error counter (real or virtual) reaches its
threshold value.
There shall be no additional objects for the Loss of PRes cummulation and threshold countersregardless of the number of virtual node IDs configured on a node. The already existing objects shall beused for the real node ID.

EPSG DS 302-D V1.1.1

5-15-

Mapping of more than 254 objects into one
PDO

One pair of mapping objects (PDO_RxCommParam_XXh_REC, PDO_RxMappParam_XXh_AU64 or
PDO_TxCommParam_XXh_REC, PDO_TxMappParam_XXh_AU64) is usually assigned to one
isochronous PReq or PRes frame. Up to 254 objects may be mapped by each of these objects. Thisvalue results from the maximum number of sub-indices possible.
However, mapping of more than 254 objects into one PDO frame can be achieved by using more than
one pair of mapping objects per frame.
The POWERLINK specification [1] does not forbid such a design.
In case of Tx frames it shall be assured that the ranges in the frame do not overlap each other.

EPSG DS 302-D V1.1.1

-16-

6

Additional object description

6.1

Object1400h..
PDO_RxCommParam_XXh_Rec

14FFh:

This description handles a sequence of up to 256 objects. These indices describe the communication
attributes of the RPDO channels. Mapping version, address information and message type are provided.
Index
Name
Data Type•Object CodeRECORD

CategoryCondAccess
PDO Mapping

constNo

CategoryAccess
PDO Mapping

Mrws / roNo

Sub-Index 00h: NumberOfEntries
Sub-Index
Name
Value Range
Default Value•

1400h .. 14FFh
PDO_RxCommParam_XXh_REC
PDO_CommParamRecord_TYPE

00h
NumberOfEntries
33

Sub-Index 03h: RxMessageType_U8
Sub-Index
Name
Data Type
Value Range
Default Value

02h
RxMessageType_U8
UNSIGNED80,3,4-Access shall be ro if only static mapping is provided by the device.
Value034Tab. 1DescriptionNot used. Value interpretation of sub-index 1 (= NodeID_U8) as usual
PReq (= message type PReq)
PRes (= message type PRes)

RxMessageType_U8 value interpretation

Object1800h..
PDO_TxCommParam_XXh_Rec

6.2

18FFh:

This description handles a sequence of up to 256 objects. These indices describe the communication
attributes of the TPDO channels. Mapping version and address information are provided.
Index
Name
Data Type•1800h .. 18FFh
PDO_TxCommParam_XXh_REC
PDO_CommParamRecord_TYPE

Object CodeRECORD

Category

Cond

Category
AccessPDO MappingMrwsNo

Sub-Index 01h: NodeID_U8Sub-Index
Name
Data Type
Value Range
Default Value

01h
NodeID_U8UNSIGNED80, 1 .. 254-Node ID of the PDO:
•CN: Real or virtual node ID of the PRes source. 0 may be used to indicate real node ID.

EPSG DS 302-D V1.1.1•-17-

MN: Real or virtual node ID of the PReq destination or node ID of the PResMN source. 0may be used to indicate PResMN with source node ID 240.

Object 1F81h: NMT_NodeAssignment_AU32

6.3This object assigns nodes to the NMT Master (MN). On the Controlled Node the object is conditional.
See [1] for more details.
Each sub-index in the array corresponds to the node with the node ID equal to the sub-index.
The object should be set by the system configuration.
Additional bit used:Index
Name
Data Type•

1F81h
NMT_NodeAssignment_AU32
UNSIGNED32

ARRAY

Category

MN: M
CN: Cond

Category
AccessPDO MappingM
rw, valid on resetNo

Sub-Index 01h .. FEh: NodeAssignment
Sub-Index
Name-Value Range
Default Value

Octet
2Tab. 2Object CodeBit
1601h .. FEh
NodeAssignment-Bit field, see below
0Value0b1b

Description
Conventional node
Virtual node

Property Evaluate
CNMN, CN

NMT_NodeAssignment_AU32 additional bit interpretation

Object 1F82h: NMT_FeatureFlags_U32

6.4

The Feature Flags indicate communication profile specific properties of the device given by its design.
The object shall be setup by the device firmware during system initialisation.
Additional bit used:Octet Bit
219Tab. 3

6.5

Name
Multiple PReq/PRes

TRUE
FALSE
Devicesupports Device does not support
Multiple PReq/PRes
Multiple PReq/PRes
D_DLL_MultiplePReqPRes_BOOL

NMT_FeatureFlags_U32 additional bit interpretation

Object 1F94h: NMT_PdoNodeAssign_AU8

This object assigns virtual node IDs to the real node IDs of the nodes present in the network.
The object should be set by the system configuration.

EPSG DS 302-D V1.1.1

Index
Name
Data Type•

1F94h
NMT_PdoNodeAssign_AU8
UNSIGNED8Object Code

ARRAY

Category

MN: M
CN: OAccess
PDO Mappingrw
No

Category
AccessPDO Mapping

Mrw
No

Sub-Index 00h: NumberOfEntries
Sub-Index
Name
Value Range
Default Value•-18-00h
NumberOfEntries
1..254254

Sub-Index 01h .. FEh: NodeID
Sub-Index
Name-Value Range
Default Value

01h .. FEh
NodeID_U8-0 .. 254
0Each sub-index in the array corresponds to the virtual node with the virtual node ID equal to thesub-index. The value hold by a sub-index is the real node ID.
If NodeID_U8 is zero the sub-index equals to the real node ID by default.

EPSG DS 302-D V1.1.1

App. 1-19-

Device Description Entries (normative)

Additional device description entries:
NameDescription

Type

D_DLL_MultiplePReqPRes_BOOL

Ability of a node to perform multiple PReq/PRes functions

BOOLEAN

Category
MN CN
MMDefault
MN
NCNN