IR Probe (dc42), Ramps 1.4, Digital Mode Issue (no replies)

Hello, everyone,

I have the following problem when integrating an IR Probe (https://www.duet3d.com/IRProbe) on my Ramps 1.4 with Marlin 2.0.x:

No matter what I do, the red LED on the IR Probe lights up 4 times at each start. According to this manual (https://miscsolutions.wordpress.com/mini-height-sensor-board/) this means that the IR Probe is in analog mode. But for my application I need the digital mode. So it should light up 2 times.

As described in the manual I connected the IR Probe to the z_min endstop of the ramps board and set the corresponding settings in Marlin (pullups for z_min enabled).

#define USE_XMIN_PLUG
#define USE_YMIN_PLUG
#define USE_ZMIN_PLUG
//#define USE_XMAX_PLUG
//#define USE_YMAX_PLUG
//#define USE_ZMAX_PLUG

// coarse Endstop Settings
//#define ENDSTOPPULLUPS // Comment this out (using // at the start of the line) to disable the endstop pullup resistors

#if DISABLED(ENDSTOPPULLUPS)
// fine endstop settings: Individual pullups. will be ignored if ENDSTOPPULLUPS is defined
//#define ENDSTOPPULLUP_XMAX
//#define ENDSTOPPULLUP_YMAX
//#define ENDSTOPPULLUP_ZMAX
#define ENDSTOPPULLUP_XMIN
#define ENDSTOPPULLUP_YMIN
#define ENDSTOPPULLUP_ZMIN
//#define ENDSTOPPULLUP_ZMIN_PROBE
#endif

I have already measured with the voltmeter and there are about 6 V at the IR Probe. Actually it should be 5 V. Is that a problem? I also connected a voltage divider and reduced the voltage to about 4.4 V. That did not change anything.

Nevertheless, my print head remains at a large distance above the bed, before the red LED even lights up to signal the actual "triggering" of the IR Probe.

Does anyone have any experience with this and could please help me? I have already worked my way through the "Configuration.h" several times and don't know what to do.

I also saw this post: [reprap.org]
Didn't help either, unfortunately.

Many greetings
Robin