104 CoDeSys 2.3 Runtime EnvironmentWAGO-I/O-SYSTEM 750I/O-IPC-C10E, CANopen Master11.5.8.1 Limitations of the CoDeSys VisualizationThe visualization integrated in CoDeSys has the three variants "HMI","TargetVisu" and "WebVisu", which are all supported by the I/O-IPC. Dependingon the process variant, there are technological limitations.Several options of the complex visualization objects "Alarm" and "Trend" areonly provided by the "HMI" version. This applies for example to the sending ofemails as a response to an alarm or to the navigation through historical trend dataas well as the creation of the data.In comparison to "HMI", Web visualization on the I/O-IPC is carried out withinsignificantly narrower physical limits. While "HMI" can access almost unlimitedresources on a desktop PC, the following limitations must be observed when usingWeb visualization:Adaptation to the File SystemThe overall size of the PLC program, visualization files, bitmaps, log files,configuration files etc. must fit into the file system.Process Data MemoryWeb visualization uses its own protocol for the exchange of process data betweenapplet and control. In doing so, process data is transmitted ASCII coded. Thepipe-symbol ("|") is used between two process values as a separating character.Therefore, the space requirement for a process data variable in the process datamemory is dependent not only on the data type, but also on the process valueitself. Thus, a variable of the "WORD" type occupies between one byte for thevalues 0 through 9 and five bytes for values from 10000.The selected format (ASCII + |) only permits a rough estimate of the spacerequirement for the individual process data in the process data buffer. If the sizeof the ASCII coded process data is exceeded, Web visualization no longer worksaccording to expectations.
