Mapping Data Attributes to PLC Memory

Introduction

You can use the I/O Mapping window to link IEC 61850 client and IEC 61850 server data items to memory locations in the PLC. You can access data items by navigating through the IEC 61850 protocol data structure:

IED → LDevice → LNode → Functional Constraint (FC)

The I/O Mapping window supports the following functional constraints:

FC	Server	Client	Description
BR	–	√	Buffered report control block
CF	–	–	Configuration value
CO	√	√	Process control service command or status
DC	–	–	Description attribute
GO	–	√	GOOSE report control block
MX	√	√	Process measurement value
RP	–	√	Unbuffered report control block
ST	√	√	Process status value
√ The FC is supported. – The FC is not supported.

There are three groups of data items:

System items contain the operating status of a module. System data items, for both the client and server, are automatically mapped to the PLC. You cannot add items to, or delete items from, the system data table is fixed.
Parameter items can originate with either the client or the server. No parameters are mapped to the PLC by default. You can add both client and server data objects and data attributes to the mapping table.
Control block items contain data provided by the following control blocks and services:
- unbuffered report control blocks (RP)
- buffered report control blocks (BR)
- GOOSE control blocks (GO)
- process control service command (CO)
- polling group service

NOTE: Polling group service data items are not displayed by the Modicon IEC 61850 Configuration Tool. Instead, they are included in the data structure created by Control Expert when you click the Update application button in the Configuration tab of the BMENOP0300 module Properties window.

Viewing System Data Items

To view system data items, follow these steps:

Step	Action
1	In the I/O Mapping window, select one of the following: Server to display data items for the IEC 61850 server Client to display data items for the IEC 61850 client
2	Click the System tab. The mapping table displays system data items for the module in its role as server or client.

Adding Parameter Data Items

To add parameter data items, follow these steps:

Step	Action
1	In the I/O Mapping window, select one of the following: Server to display data items for the IEC 61850 server Client to display data items for the IEC 61850 client
2	Click the Parameters tab. The Data Object Filter presents data objects associated with the selected tab.
3	In the Data Object Filter, make the following selections: In the IED list, select an IED. NOTE: If you selected Server in step 1, the server IED is pre-selected. In the LDevice list, select a device. In the LNode list, select the logical node object that contains the data object (attributes) you want to map to an address in the PLC. In the FC list, select the functional constraint for the data attributes you want to map to an address in the PLC. The Data Object Filter displays the associated data objects and data attributes.
4	Select a data object or data attribute in the Data Object Filter, and then drag it to the mapping table in the Parameters tab. If you selected a: Data object: The data object and all its associated data attributes are added to the table. Data attribute: Only the selected data attribute is added to the table. NOTE: The data object order of data mapping depends on the structure defined in the data model.
5	If you selected Client in step 1, expand the mapping table to display each data attribute, then edit the Polling Group setting for the attribute. Settings include: Not Poll: Indicates client can update data via control block (default) Group-1 Group-2 Group-3 Group-4 Group-5
6	Repeat steps 2...5 for each data object or data attribute you want to add to map to a located memory address in the PLC.
7	Save your edits.

When you finish configuring the BMENOP0300 module, close the Modicon IEC 61850 Configuration Tool, then click Update application in the Configuration tab of the module Properties window. Control Expert creates DDT variables for each data attribute and displays each new DDT variable in the Control Expert Data Editor.

Adding Control Block and Service Data Items

To add data attributes from remote IEDs to the BMENOP0300 module in its role as IEC 61850 client, follow these steps:

Step	Action
1	In the I/O Mapping window, click Client. Result: The Data Object Filter presents the IEDs associated with the module in its role as IEC 61850 client.
2	In the I/O Mapping window, click Control Block. Result: The Data Object Filter presents data objects associated with the selected tab.
3	In the Data Object Filter, drill down to the data attributes you want to add, by making the following selections: Select an IED. Select an LDevice object. Select an LNode object. Select an FC object. Depending on the specific IED content, you can select: BR: buffered report control block RP: unbuffered report control block CO: process control value service GO: GOOSE control block Result: The Data Object Filter displays the associated data objects and data attributes.
4	Select a item in the Data Object Filter, and then drag it to the mapping table in the selected tab.
5	Repeat steps 2...4 for each data item you want to add to map to a located memory address in the PLC.
6	Save your edits.

Each block you add displays the following columns:

Element:

the name of the control block, up to thirteen ASCII character (If the original name exceeds the maximum length, a dialog asks you to edit and shorten this value.)
Variable:

the concatenation of the Element value and the device DDT
Type:

the type of mapping item: a control block or elementary variable
Device DDT:

the device DDT of the mapped item in the PAC
IED:

the name of the IED to which the mapped item belongs
Reference Path:

the IEC 61850 protocol reference path to the control block or data object
Array:

a check mark indicating this element is an array
Length:

for array elements, the number of items in the array

Removing Data Attributes from the Mapping Table

To remove one or more data attributes from a mapping table, follow these steps:

Step	Action
1	In the mapping table, select an item you want to delete.
2	Click the right mouse button to open a context menu.
3	Click Delete to remove the selected data items from the mapping table.
4	Repeat steps 1...3 for each item you want to delete.
5	Save your edits.

Export I/O Mapping File for Server IED

To export an I/O mapping file for the server IED, follow these steps:

Step	Action
1	In the I/O Mapping window, select Server.
2	Confirm that the mapping table of the server is not empty.
3	Click Export.
4	In the Save As dialog: Navigate to the location where you wish to save the mapping file. (Optionally) Change the file name. Click Save. The file, with a .map extension, is saved to the target location.

Import I/O Mapping File for Server IED

To import an I/O mapping file for the server IED, follow these steps:

Step	Action
1	In the I/O Mapping window, select Server.
2	Confirm that the mapping table of the server is not empty.
3	Click Import.
4	In the Open dialog: Navigate to and select the mapping file to be imported. NOTE: Confirm that the name of the selected mapping file is the same as the name of the server IED name. Click Open.
5	The Confirm dialog opens and asks if you want to import the selected mapping file. Click Yes.
6	If you selected a mapping file with a name different than the server IED name, an Error message displays asking you to confirm the mapping file name. Click OK and return to step 4, above.
7	If you selected a mapping file with the correct name and format, all the pre-existing mapping items in the server IED are removed, and the items in the mapping file are imported.

Export I/O Mapping File for Client IED

To export an I/O mapping file for the client IED, follow these steps:

Step	Action
1	In the I/O Mapping window, select Client.
2	In the Data Object Filter, select the name of the IED to be exported, and confirm that the mapping table of the client is not empty.
3	Click Export to generate a mapping file for the selected client IED.
4	In the Save As dialog: Navigate to the location where you wish to save the mapping file. (Optionally) Change the file name. Click Save. The file, with a .map extension, is saved to the target location.

Import I/O Mapping File for Client IED

To import an I/O mapping file for the client IED, follow these steps:

Step	Action
1	Confirm that the target client IED file to be imported exists.
2	In the I/O Mapping window, select Client.
3	Click Import.
4	In the Open dialog: Navigate to and select the mapping file to be imported. NOTE: Confirm that the name of the selected IED name exists in the current project. Click Open.
5	The Confirm dialog opens and asks if you want to import the selected mapping file. Click Yes.
6	If you selected an IED name that does not exist in the current project, an Error message displays asking you to confirm the IED name. Click OK and return to step 4, above.
7	If you selected an IED with the correct name and format, all the pre-existing items in the client IED are removed, and the mapping file is imported for the target client IED.

Understanding the Relationship Between the PAC Scan Time and the Quantity of I/O Data

The BMENOP0300 module cyclically exchanges data with the PAC controller. The data included in this cyclical exchange depends on the PAC scan time and the amount of data to be exchanged. You will want to apply a PAC scan time that is sufficiently long to permit the exchange of all data between the module and the controller. The following formula applies:

PAC scan time > Max[10 ms, (DataSum/150) ms]

In this formula, DataSum is the amount of input data, in bytes, that is available in the module memory of the IEC 61850 configurator.

The following examples apply the above formula to determine a minimum recommended PAC scan time:

Example	DataSum (input data to be exchanged, in bytes)	Minimum Recommended PAC Scan Time
1	300	10 ms
2	3000	20 ms