Help wiring tachometer for winder?

[achase4u]

So, I got this simple little setup

And mounting is not an issue yet - but wiring is. The specs are here.

Features & Specifications?
Measuring Range: 5-9999 / per minute (for measuring low speed 1 revolutions per minute please another first, the default is 5-9999 revolutions per minute.)
Refresh Rate: When speed within 120-1200 revolutions per minute, the refresh rate is about 0.2 to 0.5 seconds, 2400-9999 revolutions, the refresh rate is about 0.25 seconds to 0.06 seconds
Measurement Accuracy: Turn 5000 turn within about 2, 5000 turn above about 3 turn around.
Explicit Way: Adopt super bright 0.56 -inch red digital tube LED display
Input Signal: Voltage pulse signal, active contact signal, PNP and NPN proximity switch signals, hall proximity switch signal
Power supply: DC 8-15 v dc power supply
Overall Dimensions: 72x36x20 mm
Opening Size: 68x33 mm
Installation: Embedded
Hall Proximity Model: NJK-5002C
Sensor Dimention: M12x10x37mm
Detection Range: 1mm-10mm
Proximity Output Current: 200mA
Detected Objects: Magnet
Sensor Wiring: brown-Power+, blue-Power-, black-signal
Operating Temperature: 0 to 50?C.
Connection Pin Description:
This is anode DC8-15V input Dc power supply pins.
This is a cathode input dc power supply pins.
This is a signal input pin.
Package Include?
Tachometer x 1
Hall NPN proximity sensor x 1
Magnet x 1




So I mounted the sensor and magnet.

I also tested wiring the readout screen and I get power and a 0. So that seems fine. However, there were no instructions on wiring the readout to the sensor. The sensor has +v and -v and a signal wire. So naturally, I wired the signal wire to the "input" wire of the readout board. Unfortunately, I got no reading when the winder turned. I have them wired in parallel to a 9vdc PSU with 500 ma.

Any ideas as to why I get no reading?

[Jim Darr]

Perhaps the sensor needs to be grounded to the controller/readout box????

[achase4u]

Thanks, Jim!

Perhaps the sensor needs to be grounded to the controller/readout box????

I appreciate the reply.

Hmmm. This is where my lack of knowledge in fundamental electronics gets me.

If there is a +v and - V, those are both live and opposite polarity? Hence no ground/2 prong power adapter?

The readout PCB shows +12v, gnd and IN. Perhaps I connected the readout box wrong. I think I connected gnd to -V...

A bit lost here.

[achase4u]

Looks like I got it. Would be nice if they had said polarity was inmportant on the magnet! I flippedi t around and got readings.

[Jim Darr]

Glad you figured it out!