This example deals with a cylinder that has only one end position (home position), either fully retracted or fully extended. The process is modeled in the logic layer, and parameters are assigned and settings changed in the system layer.
In this example, we have a cylinder with only one end position in the home position. This means that the cylinder can be either extended or retracted, but has no intermediate positions. When the cylinder is in the home position, it is either fully extended or fully retracted.
The aim of this tutorial is to correctly model the process in the logic layer and correctly assign the parameters in the system layer according to the zones. A lot of background information is also provided.
Logic layer:
Two InOut zones are modelled in the system layer. The zone for the home position is a InOut zone that controls the valve for the home position and queries the end position in the home position. This means that the valve is activated to move the cylinder to the home position and that the end position of the cylinder in the home position is monitored to ensure that the cylinder is positioned correctly.
For the work position, the home position zone is inverted. This means that the input used in the home position to control the valve and query the end position is reversed. This is done to ensure that the cylinder is in the working position and not in the home position. By inverting the input, the valve is deactivated and the end position of the cylinder in the working position is monitored to ensure that the cylinder is correctly positioned.
Properties are changed for this in the settings in this zone:
- The output is the valve for the work position
- "Keep-Alive" must be selected, i.e. set to "true" and a time delay for the input must also be assigned
