Suggestions about wiring of hall sensors in a situation I have

I have a 7i77 connected to a 7i64

I have hall sensors on the lathe (103sr-13A-2 sensing.honeywell.com/honeywell-sensing-...heet-005971-1-en.pdf). These pins must be pulled high when off and ground when off. I have 33k resistors bringing each up so that I do not draw too much power through them.

The old lathe wiring had these running at 12VDC and I have them at the same. The hall sensors output a high signal when off and a low when on. I can also run these hall sensors at 24VDC, however I have not done so yet.

Measuring at the 7i77 between the field ground and the signal wires I am measuring 10.4VDC.

I just found from page 17 of the 7i77, I see I require 14.4VDC to trip high and 9.6V to be sensed as low.

As of now, I have a few options. I can send the hall sensors to 24VDC or I can get optoisolators. I was hoping to talk to someone else before I continue with this.

Lastly, can my username be invited to LinuxCNC?

I realize I made a mistake with my prior measurements. I am reading 4.4VDC when 12VDC is supplied on the high output line. This goes to 0 when triggered. The 10VDC was just noise in the system.

Testing with an external hall sensor, the 24VDC does not have any issue. I then pumped it to 24VDC and found that the output signal was 10.4VDC.

As 33000k resistor on 24VDC is pulling it up, that means the sinking inputs would have (I believe) a 9.3k resistor. In order for me to produce a 60% signal of 24VDC (14.4VDC) to register a high, I need to replace my pull up resistors with something less than a 6k.

Above equations were using the voltage divider equation Vout=Vin*Rdown/(Rdown+Rup) where Rdown is the pull down resistor on the board and Rup is my pull up resistor.

Checking, a 6k resistor would have a maximum pull down current through the hall of 6.6mA. I can have a maximum of 20mA on the hall, so using a 3300 ohm resistor would be fine as it would draw ~10mA.

Suggestions or comments?

I replaced all the pull up resistors with 3.3k resistors. The hall sensors now read 21VDC when on and 0.1V when off. The hall has ~9mA going through it.

Overall success.

Yeah, sorry, the IRC. I know it has changed a bit since I was last on. I made my username registered, then it said I needed to be invited to #LinuxCNC