Problem solved!

A good tip was that the sensor does not need 5v.
However, the homex / y / z.g files from e.g. G1 H2 Z5 F6000 must be changed to G1 S2 Z5 F6000 (H to S). Now the motors stop when the sensor is triggered.

Thx for Help.

I could not find the original data sheet because the manufacturer (germanreprap.com) has closed its forum.
But maybe the pictures will help:

Three resistors are installed on the back of the sensors: 1002, 1800, 2200

Hi all,

I also have problems with the optical endstops. The board I have is the Duet2Wifi v1.04 and the endstops are TCST2103 5v optical sensors (https://www.vishay.com/docs/81147/tcst2103.pdf).

VCC is connected to 5v Powersupply
GND to GND on the endstop-pin on the Board
SIG to STP/IN on the endstop-pin on the Board

The endstops are in the config.g File set to Active-High (M574 X2 Y2 Z2 S1).

If the sensors are triggered, the endstop LEDs on the board go out. But nothing happens in web control -> it shows all sensors are triggered.
No i have measured the sensor signals:
If the sensor is triggered, the output is 4.3v
If the sensor is not triggered, the output is 1.5v, and not 0v or GND...

Have I missed something or are my sensors just crap?

Thanks for Help.