I’ve spent a little over two hours searching the forums now and have had little luck. Although I’ve gained some new valuable information I still have a pitfall in my knowledge. I’ve reviewed all the threads I’ve found and searched the official schematic for the sensor and I am still a little confused . I was wondering if someone could post a simple diagram of the wiring (because i can’t find where the four prong connector goes.) or if they could give a simple “verbal” walk through in it’s connection. Is my problem with the external connection of pins 3 & 4, or am i just missing something obvious. Anyway any help is appreciated and thanks in advance.
Cut the male end off of a PWM cable. Connect the red wire to pin 1, the white wire to pin 2, and the black wire to pins 3 and 4. Then plug the female end of the cable into the input on the RC.
I can’t thank you enough, we’ll start on this right away… Thanks again
You are forgetting the regulated power supply protection.
(That last line is satire.)
That is only necessary if the voltage supply is very noisy. I’m pretty sure that the outputs on the RC are fairly stable and well-regulated, so you can connect the sensor directly to the RC. Or was that satire too?
Sure you can. Just be sure to stop by and say hey in the pits at Sacramento.
“The on-chip voltage regulator provides immunity to power supply variations between 4.5V and 26.5V. However, even while operating from a regulated line, some supply and output filtering is required to provide immunity to coupled and injected noise on the supply line.” – ATS660LSB Data Sheet, Pg 10
I would recommend following the circuit for regulated power supply. The use of a metal film 20 ohm resistor will also provide a little power protection should the device or the wiring short. The capacitor on that line will also kill some of the noise that might be present with all the brush tye motors running close by. The pullup load resistor may not be needed with the input circuitry of the RC.
I found out what I was doing wrong when I was testing the Hall Effect gear tooth sensor thanks to these forms. I was not putting enough load on the circuit with just the oscilloscope. The data sheet showed that by placing a 500 ohm resister (RL) between the supply and the output, I was able to get a nice square wave and a steady frequency reading. I had to set up a chain ring in the drill press, because just waving a piece of metal past it gave very poor results.
Time for my $.02. Personally speaking, I would put the filter on it, just because it seems like a sensible idea and it seems pretty easy. Ever heard the term ‘An ounce of prevention is worth a pound of cure’? Well, old cliches are often true (That’s why they become cliches!). Use the instructions Al gave you, or look at the datasheet (I think they have an application circuit…). Even if you don’t end up needing it, it will feel better to have some padding between it and whatever voltage fluxuations you may encounter.
Okay here is my problem.
We have wired the sensor as discribed, but the that will only plug into 1 pwm per sensor.
Discussions state that you need to plug A phase into pwm6 and B into pwm 1
how do you wire one sensor to the 2 pwms?
The data sheet shows only one output per device. The output state is different depending on which direction the teeth are passing the sensor. You need to make that interpretation in software.
Please cite the discussion about A phase and B phase.
First, I assume you mean dig io, not pwm!
Second, in using Hall sensors, you actually need two placed closely together with a slight offset. You can reference the actual application note at http://www.allegromicro.com/techpub2/direction_detection/
The first sensor gives you phaseA; the second, phaseB
Ours give execllent and reproducible results. The trick is mounting them. We machines out pieces of delrin to hold them in the desired configuration. Since there are magnets in them, they want to push apart!