Here's a query from one of our readers. If you have any suggestions, please respond.
(Responses received so far are at the end of the query.)
"We have a cage maker machine that makes cylindrical cages for customers (pictured alongside).
"We would like to know how many rotations the machine makes in a given time period. Is there anything that could help us with this?
"We are looking for something very simple that only tells us the number of revolutions per time unit.
"Thank you."
Binfeng Zhang
Process Improvement Engineer
OneSteel Reinforcing Pty Limited
NSW
If you have any suggestions, please email Binfeng or PACE.
Responses received:
From: Mike Feehan
Binfeng, you could try this:
I assume there is a fixed rotating part of the machine to which you could attach a “target”?
If so, you could mount a simple inductive proximity switch such that it sees the target once per revolution. The proximity switch will give you a open or closed contact and effectively a “pulse every rotation’.
The pulse could be used to trigger an input on a local counter/display or if you have a DCS or some sort of PLC control system, use it as a digital input and configure some code as a simple counter with display.
If the process is very hot or electrically noisy, an optical sensor and target may work better.
You could also maybe do this all mechanically.
Or, if the machine rotates with the cage on it, I assume it may have some sort of VSD or servo drive, in which case you should be able to get the shaft RPM already.
Good luck.
Mike Feehan
Instrument Engineer
Instreng Pty Ltd.
From: Graeme Murphy
What is the approximate rate or rotation?
Does it always rotate in the same direction?
A simple rev counter with some reflective tape attached would do. i.e. Hioki 3404 will provide a display based upon the rate of time the reflective tape passes… or when a wheel is placed against the drum this is a rate of rotation… if its working at a constant speed then this would be a simple quick measure..
For a permanently installed system.. I would use a proximity sensor so it would count pulses of the spokes as they go around… (assuming it rotates in the same direction that is!). This is an example of a proximity sensor.
You just need to be careful if you select NPN or PNP and make sure your logger supports the one you get!
To read and log the prox sensor I would tend to use a dataTaker DT80 series logger because they can be connected to an Ethernet network. You can then connect it up to your system either via modbus or a browser to monitor/graph the values in real time and or download them..versions of the DT80 also have a display panel. There are cheaper options around than the datataker but we find it very useful because you can massively customize it… for example you may want to NOT measure whilst there is a change over. You may want to record the duration of the movement and the duration of the change over… etc… etc.. A basic logger to solve this problem would be the Fourier Daqpro which work well if you just want the rotation speed numbers and that’s all, but usually when people see the data they want other measurements, that’s why the datataker is a good option.
Graeme Murphy
Product Manager
Tech-Rentals Pty Ltd
Phone: 03 98963067
From: John Cunningham
Hi Binfeng
We have received the below enquiry via PACE magazine.
"We have a cage maker machine that makes cylindrical cages for customers (pictured alongside).
"We would like to know how many rotations the machine makes in a given time period. Is there anything that could help us with this?
"We are looking for something very simple that only tells us the number of revolutions per time unit."
There is many different possible ways to count the number or revolutions but a simple pulse generator and counter display may be suitable, but where you can mount the generator will influence the products selected.
Can you please call me to discuss
Kind Regards
John Cunningham
Motion Technologies Pty Ltd
Phone: 02 9524 4782
Resders are welcome to offer additional solutions in the comments box below.