Which products are affected?
EVS93xx-EK V7.1, EVS93xx-CK V7.1
What happens?
If the control voltage is switched on at the drive controller, the current position of the feedback system (applications with resolver or absolute value encoder) is not always indicated with reference to the machine axis scaling of the cam profile.
Sporadically, the position value is indicated by one clock pulse length outside the traversing range of the cam profile (y-axis of the cam profile). When the cam profile is traversed, the display of the current axis position sporadically jumps by one or several clock pulses.
Example: A cam profile application has a traversing range of 0 ° … 360 °. When the error has occurred, the cam profile axis still moves correctly but the current axis position is displayed incorrectly in a range from 360 ° ... 720 °.
After switch-on the current position of the feedback system should, related to the machine axis, be indicated as position value within the traversing range at the CCTRL2-PHI-ACT output (CCTRL2 function block).
The scaled traversing range should not be left while the cam operation is running.
When does the problem occur?
On the one hand the axis position is displayed incorrectly when the drive axis has been switched on. On the other hand the axis position displayed sporadically jumps by one clock pulse length during operation.
Possible diagnostics?
Monitor the position value at CCTRL2-PHI-ACT or check code C1339/003 for exceeded value ranges.
Short-term measures/recommendations?
Provided that CCTRL2-PHI-ACT is monitored the position value outside the traversing range can be corrected by the drive controller or by higher-level control and then be calculated to the valid position range.
An integrator (e. g. PHINT4) can be loaded with the calculated value. When the loading process has been completed, the integrator takes over the function of CCTRL2-PHI-ACT for the assignment of the machine traversing range, i.e. the traversing range is no longer derived from CCTRL2-PHI-ACT but only from PHINT4-OUT.
Details concerning the function of the function blocks mentioned are provided in the product documentation of the 9300EK servo controller.
Evaluation:
The function restrictions are relevant for applications in which an absolute phase reference of the drive to the machine axis is required, e. g. if an absolute value encoder is used as feedback system. In case of applications which do require this absolute phase reference, e. g. multi-axis applications with connected tools, a mechanical collision may occur in case of nonobservance.
Drives, in case of which the reference to the machine axis is generated relatively, e. g. by executing a conventional homing after switch-on, normally do not require the restricted function.
The drive itself moves correctly as long as no traversing actions (e. g. positionings) are derived from the current position CCTRL2-PHI-ACT. In this case the position is displayed incorrectly only.
If further (traversing) actions are to be derived from the current position CCTRL2-PHI-ACT the external position formation mentioned under short-term measures/recommendations must be used.
Existent applications with firmware versions < V7.1 are not affected by the function restriction since the CCTRL2 function block has not been available on previous versions of the 9300EK devices.
