Negative servo lag limit exceeded
This error message is triggered by the diagnosis module if the current servo lag limit (e1 error ID435 "e1=w1-x1 Visu.[Ax]") is less than the negative limit value entered in Parameter ID51 "Loca.dif.neg.max[Ax]”,
The error response time can be parameterised in parameter ID64 "e1 e2 response time". The higher the response time, the more robust the monitoring is against malfunctions, however the longer the switch-off time too in case of errors.
The rotary encoder of axle 1 is always used for position control, i.e. hardware interface X24. If the negative servo lag limit is to be given for the load, a gear unit may possibly have to be taken into consideration, after acknowledging the error, the rotary encoder is reinitialised and if necessary the home position run is restarted.
The error is fatal and leads to immediate shutoff of the drive controller. In this case the drive coasts to a standstill. Renewed release of the drive by the controller is prevented until the cause of the error has been corrected and the error has been acknowledged.
Source and Remedy
If a position control drive has a load-side pick-up and an overload between the motor and load clutch, the servo lag can be triggered by the overload clutch slipping through. Reduce mechanical load.
The load controller’s dynamic response setting is inadequate or too high, so that the position controller vibrates.
Optimise the proportional gain (parameter ID408 "Kv position controller [Ax]") of the position controller.
Parameterise the negative limit to a smaller value (parameter ID51 "Loca.dif.neg.max [Ax]").
Faulty position setpoint generation. Check position setpoint via parameter ID434 "W1 Visu. [Ax]”.
Faulty actual position acquisition.
Check actual position via parameter ID433 "X1 Visu. [Ax]”.
Check parameterisation e.g. of ID85 "pick-up attachment [Ax]", ID88 "pick-up PPR count [Ax]", ID112 "pick-up active [Ax]" and ID113 "evaluation mode [Ax]".
Check the serial communication between the absolute encoder and M drive.
If the mechanical load is too large (overload) the drive can no longer follow the position setpoints and the servo lag steadily increases. In this case the setpoint torque current D484 "isq-setpt I-controller" has reached the maximum torque current ID462 "Max Mom.Current" (red LED of display field H21).
If possible, e.g. for short-term higher loads, increase the ID462 "Max Mom.Current" or reduce the mechanical load.
Parameterise the negative limit to a smaller value (parameter ID51 "Loca.dif.neg.max [Ax]").
Malcommutation can lead to increased power demand for synchronous machines. This case occurs, e.g., if the position pick-up system provides an incorrect commutation angle to the motor commutation.
Repeat the BA22 stop angle run and check the actual position acquisition (absolute encoder).
Check the parameterisation of the motor commutation, e.g. parameter ID460 "pole pair pitch [Ax]", ID468 "field current [Ax]" (For SM < 0.5, for ASM > 0.5), ID471 "slip (_1)[Ax]" (only ASM).
Check the current control function, optimise if necessary.
The error can occur in a rotating drive as a sequential fault e.g. following a malfunction in the power section Locate and correct the original cause of the error.