86 ï Fieldbus-specific AdditionsDeviceNetWAGO-I/O-SYSTEM 750I/O Modules5.2 DeviceNet5.2.1 Process Image AccessThe DeviceNet master can access the BluetoothÆ data in two ways.With predefined instances of the assembly object, digital and analog input andoutput data of a node are transmitted with a command to, or from, the master.The application in the master can then address the data in the memory. Thedata is stored in the master as it is for mapping in the coupler/controller. Thebyte-oriented module data (analog modules and special modules) and the bit-oriented module data (digital modules) are separated according to input andoutput image in the memory in "arrays of byte". Therefore, the correspondingarray and associated memory address can be determined from module type.The data in the BluetoothÆ module can be directly addressed with the analoginput point object or the analog output point object. The instance number ofthe respective object is based on the position of the module in the node.5.2.1.1 ExampleA node contains the following modules with input and output process image:3 x 750-402 for every 4 bits of input data,1 x 750-452 4 bytes of input data,1 x 750-644 12 bytes of input and 12 bytes of output data,1 x 750-550 4 bytes of output data,1 x 750-452 4 bytes of input data,1 x 750-550 4 bytes of output data,1 x 750-452 4 bytes of input data,1 x 750-504 4 bits of output data.The BluetoothÆ module uses a process image of 12 bytes with a mailbox sizeof 6 bytes. The mailbox is unmasked.
