Voltage Monitoring Function Of Encoder Supply - HEIDENHAIN PWM 8 Operating Instructions Manual

Basic circuit diagram of power supply of encoder and PWM 8 with 24V power supply unit and
subsequent electronics connected (HTL with interface board):
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Note on HTL interface boards:
If the encoder voltage of the HTL interface board is set to INTERNAL and at the same time a subsequent
electronics connected to the OUT flange socket of the interface board, the switching regulator in PWM 8 tries
to set (clamp) the encoder voltage to that of the subsequent electronics. PWM 8 is not permanently adjusted
to the encoder voltage of the subsequent electronics; it is only adjusted when the PWM 8 is switched on,
when the encoder voltage is switched on or off or the encoder supply is set to INTERNAL. If there is no
subsequent electronics connected, the switching regulator provides 12V in the standard setting. With the
HTL interface board potential segregation of voltage, subsequent electronics and encoder voltage is not
possible.

6.1.4 Voltage Monitoring Function of Encoder Supply

If the encoder supply is set to EXTERNAL and parameter P2 U-MSYS EXTERN set to FLOATING, PWM 8
checks the voltage of the subsequent electronics. In order to switch the encoder voltage to EXTERNAL the
subsequent electronics must at least provide the power-on current for potential segregation and for the
switching regulator. If this is not the case, the following message is displayed:
Note:
If parameter P2 U-MSYS EXTERN is set to FLOATING, the potential segregation and the switching regulator
in PWM 8 can be switched off by setting P2 to FROM CUSTOMER.
This reduces the power consumption from the subsequent electronics (see section 5.2.2 PARAMETERS,
Parameter P2).
When using the HTL interface board, parameter P2 is not available. Potential segregation is not possible in
this case.
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This soft key serves to confirm the message.
The encoder supply is reset to INTERNAL
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