ZF Electronics produces a variety of industrial automation and HMI devices, which includes their GS101205 Hall effect speed sensor. This device promises near-zero speed operation detecting up to 15kHz, with unlimited mounting operations, but occasionally customers report issues with the sensor failing above low speeds but well below its 15kHz specified ceiling. What might cause this?
A leading cause of issues is that this is specifically a gear tooth sensor. Some customers attempt to use it to pick up items such as pins, bolts, nubs, flanges, or other surfaces the sensor isn’t expecting to see. This can cause gremlins in your system, up to and including total failures to operate. When designing this sensor into your system, please ensure the sensing face you’re designing it to work with meets the sensor’s specifications for proper operation. For further information, check out the product’s datasheet.
Thanks for posting this. I’m looking at the GS100701 to use to determine ground speed on an agricultural system. I was planning a plastic wrap around target with 6-32 flat head zinc-plated steel screws equidistant around the perimeter of the target. I chose those because they would be as wide as the tooth thickness the spec sheet recommends.
This system will be moving slowly - no more than 1.5 mph when operating.
The screws (aka teeth) will be much more apart than the recommended 10mm between teeth.
Based on your post, it seems this might not work well. What do you think?
I also need the output to be 24VDC ideally. I think this unit can provide that but I’m not certain.
The space it needs to go in is very tight and this unit fits it really well. If this won’t work, is there an alterative to you can recommend?
Hello, Walter.
The between-tooth distance being larger than 10mm should be work-withable, if my read of the datasheet for your sensor is correct. The specifications given are a minimum rather than a hard, must-hit target, though I would still very much test your solution prior to committing to it.
I would also recommend against using screws. Again, the device is a gear tooth sensor and is designed to look for flat, rectangular tooth-like plates rather than round devices like screws. Many, many people try to use screws or similar options because they’re easy to source and install, but you then run into the risk of gremlins I outlined above. It lowers the reliability of the system. I cannot search our system for a sensor that precisely meets your requirements more completely, but I will say that if you cannot use a gear tooth system that fits this sensor’s target specs? I’d perhaps look into using wingnuts or some other easily accessible hardware that more closely aligns with the target tooth shape, to try and claw back at least a little accuracy lost from incorrect targets.
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Thanks for the response! It’s very helpful!
I will ditch the screw idea. I can make some custom pieces to ZF’s target tooth specs (2.5 mm wide x 6.35 mm thick) and then epoxy them into place in sockets in the plastic ring, no closer than their 10mm tooth spacing. Do you think this will work ok?
Two more questions.
Will this sensor output a 24V pulse?
Will it have any trouble with the slow speed? Zero up to 1.5mph?
We are using this to get distance traveled plus or minus 1” (which is also dependent on our target geometry of course).
Some research on the topic to better understand the operating principle may be of benefit. This document has some information that may be useful. Validating function with the chosen target is necessary regardless, so one doesn’t stand to loose much from evaluating the simpler/cheaper options first.
Per the datasheet, the device provides an open-collector output. The output signal swing is therefore determined by the voltage to which the output is pulled externally.
There’s missing information regarding how your application relates target presentation to the speed in question, as well as what precisely the manufacturer means by “near zero.”
It can be confidently stated that “Near zero” is not the same as “zero” however, and recognizing that the sensor type is typically used in cases where speed is the quantity of interest rather than position, my advice would be to look for a different sensor that offers zero-rate stability if position control is what you’re after.
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