Which products are affected?
ESP-SPAC-CAM1 – Software Package Cam V1.4 (
LenzeCamControl1V0104.lib library)
What happens?
Path cams depending on the direction of rotation ('positive path cams', 'negative path cams') are not switched on again if the direction of rotation is changed several times within one cycle.
When does the problem occur?
This behaviour occurs if
- the drive passes the cycle with a specific direction of rotation and switches correctly a cam depending on the direction of rotation (e.g. cam signal from 100 ° to 200 °)
- the drive reverses its direction of rotation afterwards and passes the cam area in reverse direction. According to definition, the cam does not switch (e.g. if the cam is not switched in the area ranging from 200° to 100°)
- the drive reverses again and passes the cam area defined. In this case, the cam is not switched on although the direction of rotation and the cam area intend a switching of the cam signal (e.g. positive pass-through of the position from 100 ° to 200 °).
The problem does not occur anymore in the following cycle but only within the cycle in which the direction of rotation has been inverted.
Possible diagnostics?
The behaviour occurs if path cams depending on the direction of rotation are used and the direction of rotation is changed several times within a cycle.
Short-term measures/recommendations?
Do not use cam signals depending on the direction of rotation in function block
L_CamContactor.
If cam signals depending on the direction of rotation must be used, apply the IEC standard functions GT ('Greater than') and LT ('Less than') instead of function block
CamContactor to check the current position for its position within the cam area. An evaluation including the direction of rotation can easily be carried out by using a following AND logic with the corresponding output signals of the higher-level function block
L_CamContactorVPOS.
Note: If function block
L_CamContactor is not used, the cam signals cannot be specified via the cam profile data (LC9 file) but must be selected as separate positions in machine increments. If the switch-on/switch-off points are to be selected in user specific units [m_units], [s_units]), function block
L_CamSetPosition can be used for the conversion into machine increments.
Evaluation:
When using path cam signals depending on the direction of rotation, the cam signals are only set correctly by function block
L_CamContactor when being approached for the fist time. If the position is changed in such a way that the cam area is passed through in the opposite direction first and in the defined direction of rotation afterwards, the cam does not switch anymore. The behaviour does not occur anymore in the following cycle but only within the cycle in which the direction of rotation has been inverted.
