MC41 - M18-4 Barrel Speed sensor

Hi,

I have an MC41 module and I want to pick up the signal from a speed sensor M18-4VPFF200-Q8.

I want to measure the speed on the coupling between a motor and a torquemeter. I have a reflective sticker on the coupling, and I’m using this sensor to pick up the speed. However, when I connect the sensor, I’m reading zero on the MC41. I can see the lights on the sensor changing, which indicates the sensor is generating pulses, but the MC41 isn’t registering them.

Here’s how I connected the sensor:
Sensor pin 1 (brown): 12V
Sensor pin 2 (white): GND
Sensor pin 3 (blue): C1:12 on the MC41
Sensor pin 4 (black): C1:11 on the MC41

The max speed I want to measure on the coupling is 200RPM. I calculated the max frequency as:

Thus I calculated my Max Frequency (Hz) = (Max RPM×Pulses per Revolution)/60 = (200*1)/60 = 3.33 ~ 3 Hz

Do you have any input on whether the issue might be software or hardware related?

Thanks!