Maximum signal amplitude exceeded
The error is triggered by the pick-up monitoring module if the amplitude of the rotary encoder tracking signals (sin/cos signals) are larger than the limit value given in parameter ID285 "G-Mon.maxValue[Ax]. Monitoring is activated by bit 0 in the parameter ID280 "G-Mon.Command Ax" and can trigger a fatal error if bit 0 is set in the parameter ID282 "G-Mon.error_mask".
The limit value ID284 is set automatically if bit 1 is activate in parameter ID280 "G-Mon.Command Ax". Sin/cos signals with over-large amplitudes lead to poorer controller performance, because the AD transformers are overmodulated and the sin/cos rotary encoder behaves like a square-wave incremental encoder with a correspondingly lower resolution. Under unfavourable conditions, sin/cos signals with an over-large offset lead to an incorrect actual position. In this case, rotation in positional synchronism is no longer possible. In the case of synchronous motors, malcommutation also results.
The amplitude of the sin/cos signals is measured by calculating the measured value "m” as follows:
m = sin^2 + cos^2.
The measured value “m” is displayed in parameter ID2362 "G-Mon measured value". For ideal sin/cos signals the measured value must always be constant, for real signals the measured value should lie within certain limits.
The error response time can be parameterised in parameter ID2366 "G-Ue 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 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
Strong interfering signals can lead to an error being triggered by the rotary encoder track monitoring. Check the shielding of the rotary encoder cable.
A short circuit between the signal leads and the supply line of the rotary encoder can lead to overmodulated sin/cos signals. Check the rotary encoder lead for short circuits
In all Heidenhain rotary encoders, a defective 5V sense line can lead to the automatic rotary encoder detection assuming a Stegmann rotary encoder and therefore switching the supply voltage to 8V. In this case, the usual result is that the SMD fuses of the hardware circuit blow (error 117/121). In rare cases the signals are very highly overmodulated and the parameter ID113 "evaluation mode " is switched to value 4. In this case the rotary encoder lead should be renewed.
Defective rotary encoder. Replace rotary encoder.
Defective rotary encoder input to the rotary encoder evaluation (hardware) in the M drive. Replace M Drive.