Siemens SINUMERIK 828D Function Manual

Also see for SINUMERIK 828D Turning: Diagnostic manual Function manual Equipment manual Programming manual Operating manual

Contents

Basic FunctionsFunction Manual 09/2011, 6FC5397-0BP40-2BA0 83713P3: Basic PLC Program for SINUMERIK 840D sl13.1 Brief descriptionGeneralThe PLC basic program organizes the exchange of signals and data between the PLC user program and theNCK (Numerical Control Kernel), HMI (Human Machine Interface) and MCP (Machine Control Panel). In the caseof signals and data, a distinction is made between the following groups:• Cyclic signal exchange• Eventdriven signal exchange• MessagesCyclic signal exchangeThe cyclically-exchanged signals consist primarily of bit arrays.• They contain commands transmitted from the PLC to the NCK (such as start or stop) and status informationfrom the NCK (such as program running, interrupted, etc.).• The bit fields are organized into signals for:- Mode group- Channels- Axes/spindles- General NCK signalsThe cyclic exchange of data is performed by the basic program at the start of the PLC cycle (OB1). This ensures,for example, that the signals from the NCK remain constant throughout a cycle.Event-driven signal exchange NCK → PLCPLC functions that have to be executed as a function of the workpiece program are triggered by auxiliaryfunctions in the workpiece program. If a block with auxiliary functions is executed, the type of auxiliary functiondetermines whether the NCK has to wait for this function to execute (e.g. tool change) or whether the function willbe executed together with the workpiece machining process (e.g. tool loading on milling machines with chainmagazine).Data transfer must be as fast and yet as reliable as possible, in order to minimize the effect on the NCKmachining process. Data transfer is, therefore, interrupt- and acknowledgment-driven. The basic programevaluates the signals and data, acknowledges this to the NCK and transfers the data to the application interfaceat the start of the cycle. If the data do not require user acknowledgment, this does not affect NC processing.