3.1.5.4 Addressing

Note

For the number of input and output bits or bytes of the individually activated on I/O modules please refer to the corresponding I/O module description.

The digital module data is taken into consideration first.

CANopen does not transmit the data bit by bit. The digital module data is grouped into bytes and assigned to the corresponding index, digital input data to index 0x2000 (0x6000), digital output data to index 0x2100 (0x6200).

The assignment of bus module data having a width of 1 byte or more, are analog modules and assigned to the individual indexes.

The table shows a review of the indexes of the bus module data.

Table 3-2: Indexing of bus module data in the object directory

Every index has a maximum of 256 sub-indexes (Sub-Index 0-255).

The number of data inputs is indicated in sub-index 0, whereby the data is filled in blocks in the following sub-indexes.

The block size depends on the data width of the specific bus module.

WAGO-I/O-SYSTEM 750

CANopen

80• Fieldbus Controller 750-837, /02x-000, 750-838, /02x-000 Data Exchange

Table 3-3: Sub-indexing of the bus module data in the object directory

Note

Please refer to chapter 5.3.4.1 "Initialization" for a detailed description of how to set the default configuration.

Attention

A process image restructuring may result if a node is changed or extended. In this case the process data addresses also change in comparison with earlier ones. In the event of adding modules, take the process data of all previous modules into account.

Example:

The bus module configuration includes:

1)5 digital 2 channel input modules (i.e. 750-400),

2)one digital 4 channel output module (i.e. 750-504) and

3)two 2 channel analog output modules with 2 bytes per channel (i.e. 750-552).

to 1) Indexing the data of the 5 digital 2 channel input modules:

*) D1.1 = Data bit module 1 channel 1, D1.2 = Data bit module 1channel 2, etc.

to 2) Indexing the data of the digital 4 channel output module:

*) D1.1 = Data bit module 1 channel 1, D1.2 = Data bit module 1 channel 2, etc.

to 3) Indexing the data of the 2 analog 2 channel output modules:

*) D1.1 = Data word module 1 channel 1, D1.2 = Data word module 1 channel 2, etc.

3.1.5.4.1.2Indexing the PFC Variables

The entry of the PFC variables into the object directory is made separate according to data type (Integer8, Unsigned8, Boolean, Integer16, etc...) and input and output.

WAGO-I/O-SYSTEM 750

CANopen

Due to the fact that CANopen does not transmit the data bit by bit, the variables data of the Boolean data type are grouped into bytes and assigned to the corresponding index, input variables data of the Boolean type to index 0xA080, output variables data of the Boolean type to index 0xA500.

The assignment of variables data having a data width of 1 byte or more, are analog modules and assigned to the individual indexes.

Note

The IEC 61131-3 input variables are defined from the point of view of the CAN bus, meaning that they are regarded as output variables by the PFCs. According to this, the IEC 61131-3 output variables are regarded as input variables by the PFC.

Table 3-4: Indexing the IEC 61131-3 variables data in the object directory

Every index has a maximum of 256 sub-indexes (sub-index 0-255).

The number of data inputs is indicated in sub-index 0, whereas the data is filled in blocks in the following sub-indexes.

The block size depends on the data width of the specific data type.

Tab 3-1: Sub-indexing of the IEC 61131-3 variables data in the object directory

More Information

Please refer to chapter 5.3.4.1 "Initialization" for a detailed description of how to set the default configuration.

Example:

The following IEC 61131-3 variables were defined:

WAGO-I/O-SYSTEM 750

CANopen

82• Fieldbus Controller 750-837, /02x-000, 750-838, /02x-000 Data Exchange

1)11 input variables of the Boolean data type and

2)5 output variables of the Integer24 data type.

to 1) Indexing the data of the 11 Boolean input variables:

to 2) Indexing the data of the 5 output variables, type Integer24 :

3.1.5.4.1.3Access to the PFC variables data from the fieldbus

The program permits the byte-wise access to the data contained in the controller memory by means of the specific indexes for data types having a data width of 1 byte (Integer8, Unsigned8 and Boolean).

A specific byte for each is selected in the sub-index.

When using indexes for larger data blocks, the simultaneous access to several bytes is possible.

The index for Integer16 (0xA0C0) or for Unsigned16 (0xA100) permits for instance, to access the written PFC output variables data word-wise, the index 0xA140 for Integer24 3 byte-wise etc.

Example:

Access from the fieldbus to the PFC output data byte 512, byte 513 and byte 514 is made with the Integer or with the Unsigned data type:

The following tables show a review of addressing data having different data widths.

For this purpose, the memory space reserved for the variable’s data in the fieldbus controller (byte 512 to byte 1023) is assigned the individual indexing depending on the data width.

WAGO-I/O-SYSTEM 750

CANopen

The indexing mentioned in the tables is continued up to the individual maximum index and sub-index.

Note

From the point of view of the programmable fieldbus controller, the PFC output variables are defined, whereas from the point of view of the CAN fieldbus, these are deemed as input variables. Correspondingly, the PFC input variables are deemed as output variables for the IEC 61131-3 access by the fieldbus.

In other words: IEC 61131-3 input variable = PFC output variable

PFC input variable = IEC 61131-3 output variable.

Fig. 3-13: Correlation of IEC 61131-3 variables and PFC variables g012444e

WAGO-I/O-SYSTEM 750

CANopen

84• Fieldbus Controller 750-837, /02x-000, 750-838, /02x-000 Data Exchange

Addressing for access on PFC output variables

* A maximum of 8 Boolean values can be stored in one byte (1 sub-index), i.e. there is no bit resolution per sub-index.

WAGO-I/O-SYSTEM 750

CANopen

Addressing for access on PFC input variables

* A maximum of 8 Boolean values can be stored in one byte (1 sub-index), i.e. there is no bit resolution per sub-index.

WAGO-I/O-SYSTEM 750

CANopen

86• Fieldbus Controller 750-837, /02x-000, 750-838, /02x-000 Data Exchange

Examples of how to define PFC fieldbus variables

The following examples show some definitions for PFC variables with different data types, compared to the specific object directory entries.

Table 3-5: Examples for variable definitions with the specific object directory entries

3.1.5.4.1.4Maximum indexes

The maximum indexes and sub-indexes result from the memory size of the fieldbus controller of 512 bytes and the individual data width of the data types.

The table shows a review of the maximum indexes and sub-indexes of the IEC 61131-3 variable.