Search For RPM Sensor For Analog Devices 5B45-05 f/v

Chances are it is just a 2 wire magnetic pulse train prox that picks up the signal as the teeth pass by in a TTL input to the converter.

thanks Jimh77

it's 3 wire -,+ and signal

the problem is (in pdf) the 5B45 triggers when the input crosses zero volts or 1.4 volts when biased (it's not biased). the sensor sales guys here say it's a strange f/v converter to use for rpm, but somebody did.

also, there's a speed issue - at 10K rpm the wheel produces 10KHz and that's pretty high for a prox.

thanks again for your help

I'm thinking of ripping out 5b45 - what's a good sensor + f/v recipe to replace it with?

tommyt

I would say remove the old system and replace with a new current speed measure system. There are plenty to choose from. Digital being the most reliable and accurate. A tacho-gen may work for you.

Forget about the prox switch never going to be reliable or repeatable!

I agree with your replace idea...tach-gens are too $ for this app, however.

Unless someone responds with knowledge of the 5B45's sensor selection,

I plan to replace with a $110 3/8" spectec hall effect sensor & one of their small $40 f/v's to work with the gear tooth wheel.

I've also got a black/white wheel on the same shaft - I may look at a diffuse optic sensor. Would still replace the f/v, though. Can u recommend good one?

thanks again

tommyt

Speed is the main consideration as you know with an actual frequency of 166HZ a 300hz reaction time is what I would suggest. I know of none made today that can do that, sorry. As far as manufacturers go I normally use either Banner or Turk. I have used automation direct in the past with good results.

TommyT, I am a Measurement Engineer & I have been using Hall Effect Magnetic pick-ups with a 60 tooth gear or wheel, to aaurately measure RPM for 32 years. I have also used several other technologies including optical.

The 60 tooth gear with a magnetic pick-up is my preference, because it is 'bullet-proof' & has stood the test of time, especially in a control situation. The reason for using a 60 tooth gear is so that RPM can be read directly by any standard frequency counter in Hertz ( 60 Hz(i.e. 1/sec) per Rev/(60 sec per min) = RPM).

There are 2 different types of Hall Effect magnetic pick-ups, Passive & Active. Passive types do not require external power & have a 2 pin connector. With a 60 tooth gear it will work accurately from 300 RPM to 20,000 RPM. Active types (also known as Zero Velocity types) require power in the range typically of 5 to 24 volts DC, and will work accurately from 0 RPM to 30,000 RPM. Active pick-ups require a specific mounting orientation whereas most Passive types do not.

I can send info on Manufacturer's that I use. I also have good used pick-ups of both types.

On the Analog Devices Module, either type should work fine. A negative trigger voltage should not be a problem. Paul

If you do not need to sense zero or very low speeds then a common passive (self generating) magnetic speed pickup will work. Look at this page and scroll down to the "Principles of Operation" section:

http://www.motionsensors.com/speed-sensors/variable-reluctance-speed-sensors.shtml

There are many manufacturers of similar sensors.

If you do need to sense very low or zero speed then one of the powered hall effect types would probably do OK.

Optical is difficult if you need to sense in dirty environments so I tend to avoid it. Just about everything I have anything to do with is dirty in one way or another.