FAQ for step motor control in Cave A
- Q: Why does the IEF-GUI always yield an error when talking to the hardware?
A: There is a communication problem with the IEF-Controller. Possible problems are:
- No connection via ProfiBUS
- The IEF-Controller is not switched on
- The IEF-Controller is in manual mode
- Q: What to do, if there is a communication problem with the IEF-Controller? A:
- Check, that the OPC Server (TwinCAT) is running. The icon on the lower right of the task bar should be green. If it is red, right mouse click that TwinCAT icon -> System -> Start
- Check the physical connection of the Profibus cable
- Switch the terminators on both ends of the Profibus cable to ON
- Q: How to switch the IEF-Controller from manual to "automatic" mode?
A: By pressing escape on the front panel of the physical hardware controller and following the menu, switch the controller to the "automatic" state.
- Q: I want to do manual stuff at the controller itself, but I can not switch it to "Manual" mode. A:
- Quit the LabVIEW program (unload the IEF-Controller class). Then, the IEF-Controller switches from on-line to automatic mode.
- If that does not work, switch off the IEF-Controller off and on again.
- Q: I think everything is o.k., but I can not control the IEF-stuff from the GUI.
A: Do a "Reset Controller" at the GUI. That should switch the IEF-Controller to on-line mode.
- Q: I have switched the IEF-Controller off and on again. Do I have to restart LabVIEW?
A: No, just click on "Reset Controller" on the IEF-GUI.
Next to the normal system classes (SuperProc, Listener, DSCInterface, ...), the step motor control uses three other classes.
- IEF-Controller: Represent the control unit PA-Control from IEF-Werner
- IEF-Axis represents an axis of that control unit. It does not communicate with the PA-Control but only with an object of the PA-Controller class. Only the tags for position and status of an axis are registered as "dsctrend" events and are transmitted from the PA-Control via the DSCInterface process.
- IEF-GUI is a GUI that talks to a set of axes.
The control unit PA-Control is connected via Profibus to the PCI Profibus-master card from Beckhoff. The TwinCAT software is used to configure the Profibus and the OPC-Server from Beckhoff and is needed to publish/subscribe data of/to the Profibus.TwinCAT is connected via the OPC-Server and OPC to the DSC (Datalogging & Supervisory Control) module of LabVIEW. For runtime systems of CS, the runtime system of the DSC module is required and must be purchased. Like this, the Profibus tags used by the PA-Control are available as DSC tags in the LabVIEW environment.
The class IEF-Controller controls the PA-Control by writing to and reading from the DSC tags of the DSC engine. Objects of the class PA-Control must run on the same PC as the DSCIntProc object. In principle, the objects of the IEF-Axis and the IEF-GUI classes may run on different nodes than the IEF-Controller.
- 06 Jul 2005