WAGO I/O System 750 Series Manual

Also see for I/O System 750 Series: Manual Manual Manual Manual

Contents

Fieldbus Coupler • 49Fieldbus Coupler 750-346WAGO-I/O-SYSTEM 750DeviceNet3.1.4 Process ImageAfter powering up, the coupler recognizes all I/O modules plugged into thenode which supply or wait for data (data width/bit width > 0). In the nodesanalog and digital I/O modules can be mixed.The coupler produces an internal process image from the data width and thetype of I/O module as well as the position of the I/O modules in the node. It isdivided into an input and an output data area.The data of the digital I/O modules is bit orientated, i.e. the data exchange ismade bit for bit. The analog I/O modules are all byte orientated I/O modules,i.e. modules where the data exchange is made byte for byte. These I/O mod-ules include for example the counter modules, I/O modules for angle and pathmeasurement as well as the communication modules.NoteFor the number of input and output bits or bytes of the individual I/O modulesplease refer to the corresponding I/O module description.The data of the I/O modules is separated for the local input and output processimage in the sequence of their position after the coupler in the individual proc-ess image.In the respective I/O area, analog modules are mapped first, then all digitalmodules, even if the order of the connected analog and digital modules doesnot comply with this order. The digital channels are grouped, each of thesegroups having a data width of 1 byte. Should the number of digital I/Os ex-ceed 8 bits, the coupler automatically starts another byte.NoteA process image restructuring may result if a node is changed or extended. Inthis case the process data addresses also change in comparison with earlierones. In the event of adding a module, take the process data of all previousmodules into account.