42 • Fieldbus coupler/controller Fieldbus controller 750-819

Attention

The I/O module data must be copyed into the PFC variables via the IEC 61131-3 application program, in order to be processed by the Neuron-Chip.

Note

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.

3.2.6 Data exchange

With LON, the transmission and exchange of data is made using objects network variables.

A network variable (NV) is a type based variable in the Neuron-C programming language for the realisation of logical communication channels between LON®- nodes. If data is transferred from a node to the network, this is made using the network output variable (nvo), if data is transferred from the network to a node this is made using the network input variable (nvi).

For the exchange of I/O data the coupler provides an assigned value of network input and output variables. This number depends on the selected network interface of the Neuron-C application TOPLON® PRIO.

For the access on the PFC variables data, in TOPLON® PRIO a so-called Symbol-file (Sym-file) will be imported.

This file contents all defined IEC 61131-3 variables and will be created in the programming software WAGO-I/O-PRO 32. After the import in WAGO TOPLON® PRIO all defined boolean and other PFC input and output variables according IEC 61131-3 are automatically available in the plug-in for further processing.

More information

i Please find a detailled description on handling of the IEC 61131-3 programming software WAGO-I/O-PRO 32 in the respective manual (Item no.: 759- 120/000-002).

The Software configuration handling in the plug-in WAGO TOPLON® PRIO is extensive explained in the corresponding manual to this plug-in (Item no.: 759-123/000-002 part 5).

Modular I/O System

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3.2.6.1 Memory areas

The controller uses a memory space of 256 words (word 0 ... 255) for the physical input and output data.

Attention

The physical I/O module data can only be read internal by the CPU. The data must be copyed into the PFC variables via the IEC 61131-3 program, in order to be processed by the Neuron-Chip and accessed from the fieldbus side.

The controller is assigned an additional memory space for mapping the PFC variables defined according to IEC 61131-3. This extended memory space (word 256 ... 511 each) is used to map the PFC variables behind the physical process image.

1The data of the input modules can only be read internal by the CPU. Via the IEC 61131-3 program they can be processed or directly copyed on PFC output variables.

2In the same manner, writing to the output modules is only possible from the CPU.

3Transferring data from the fieldbus side to the controller is made using network input variables (nivs). These are either processed in the NeuronChip via the Neuron-C application or directly transmitted and written to the memory area of the PFC input variables via the Dual-Port-RAM. Subsequently the data can be read by the CPU in order to be processed.

4Once the data has been processed through the IEC 61131-3 program, the CPU writes the variable data to the memory area of the PFC output variables.

The variables are transferred to the Neuron-Chip via the DPRAM and processed in the Neuron-C application. Subsequently the data can be accessed from the fieldbus side using network output variables (nvos).

Modular I/O System

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44 • Fieldbus coupler/controller Fieldbus controller 750-819

In addition, the controller offers further memory spaces.

A special memory space is reserved for the variables used for external configuration. The binding of the configuration variables with the so-called Configuration Properties (CPs) bind them permanently.

CPs are variables comparable to nvis that are used for the external controller configuration via the LON network. As opposed to the nvis, the settings via CPs are stored in the LNS data base and in the EEPROM of the Neuron-Chip. Thus they are still available after a reset and they can be subsequently accessed when changing the node for example.

The address range of the configuration variables spans 128 double words.

The following memory spaces inside the controller cannot be accessed from the fieldbus side:

RAM The RAM memory is used to create variables not required for communication with the interfaces but for internal processing, such as computation of results.

Retain The retain memory is a non-volatile memory, i.e. all values are retained following a voltage failure. The memory management is automatic. In this memory area, flags for the IEC 61131-3 program are filed together with variables without memory space addressing or variables which are explicitly defined with "var retain".

Note

The automatic memory management can cause a data overlap. For this reason, we recommend not to use a mix of flags and retain variables.

Code The IEC 61131-3 program is filed in the code memory. The code memory memory is a flash ROM. Once the supply voltage is applied, the program is transmitted from the flash to the RAM memory. After

an error-free start-up, the PFC cycle starts when the operating mode switch is turned to its upper position or by a start command from WAGO-I/O-PRO 32.

Modular I/O System

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