HEIDENHAIN PWM 8 Operating Instructions Manual page 34

If in the OPTIONS soft-key row the encoder supply is set to EXTERNAL and parameter P2
U-MSYS EXTERN to FLOATING, PWM 8 checks the voltage of the subsequent electronics. If the voltage
drops to approx. 4.5V trouble-free functioning of potential segregation and switching regulator can no longer
be guaranteed; a warning is displayed:
When this warning is displayed, the encoder supply must be switched to INTERNAL. The warning can be
ignored, if desired.
In this case the warning is no longer displayed. (However a warning is displayed in the INFO MODE). To
be on the safe side, the encoder supply is switched off. The operator must reactivate it in the OPTIONS
soft-key row. Afterwards, trouble-free functioning of PWM 8 can no longer be guaranteed and must be
observed by the operator.
If the voltage of the subsequent electronics falls below 3V, another warning is displayed requesting the
operator to switch the encoder supply to INTERNAL:
Warning: The voltage of the subsequent electronics is too
low to power the encoder. The power supply of the encoder
has been switched off to be on the safe side.
The warning can be ignored by pressing this soft key
Press this soft key to switch the encoder supply to
INTERNAL and clear the warning
Press this soft key to switch the encoder supply
to INTERNAL
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