Hello all
I have a question regarding to converting AC voltage which is the output of proximity to 4-20mA , our purpose is monitoring the output of proximity without using vibration card, we are going to know if it is possible to monitor the output of proximity by using special kind of converter. We are searching for a converter to do the same job as vibration card, what I mean is converting proximity output( which is ac voltage+ dc offset) to 4-20 mA. Does anyone know any special kind of converters or device for that?

 

Dude,

I think we've been through this "dance" before with you. It's called "20 Questions" to try to understand what it is you are asking about--and while I know English is probably not your native tongue, you seem to be reasonably proficient at it (at least in writing). Think about how you would respond to a question like this with your knowledge and experience. And, then start from scratch with the basic information you would need to offer a quick and concise response. U REALLY need to be more specific about the equipment you are trying to interface to and with. There are ALL kinds of converters available, but not all of them work with every different kind of vibration sensor or pick-up. And, many vibration sensors are considered proprietary by the manufacturer.

In the industrial world, there are LOTS of converters--for just about everything (unfortunately, in my personal opinion--lots of them are not very good and not very robust). Use your preferred World Wide Web search engine and look for "proximity probe converters" and start there, and you will see some relevant searches with different equipment and terms and words you can also try searching with.

If I posted to an anonymous World Wide Web forum that my watch wasn't working and asking for help with repairing it, and you read the post, what would you say? HOW MANY questions would you have to ask to even begin providing useful information? Or would you just say, "Change the battery," without even knowing if the watch was electronic or mechanical (I wear an older self-winding watch). Would you ask if the display was working? (Remember my watch has hands--three of them.) Your question is similar in nature. There are several manufacturers of proximity vibration probes/sensors/pick-ups, and you didn't tell us ANYTHING about the ones you are trying to work with (without buying the proper card to interface with).

So, GET A CLUE and GIVE US A CLUE--and you will most likely be happy with the results. But we gotta have some basic information.

Or don't; it's your choice.

 

Dude,

I think we've been through this "dance" before with you. It's called "20 Questions" to try to understand what it is you are asking about--and while I know English is probably not your native tongue, you seem to be reasonably proficient at it (at least in writing). Think about how you would respond to a question like this with your knowledge and experience. And, then start from scratch with the basic information you would need to offer a quick and concise response. U REALLY need to be more specific about the equipment you are trying to interface to and with. There are ALL kinds of converters available, but not all of them work with every different kind of vibration sensor or pick-up. And, many vibration sensors are considered proprietary by the manufacturer.

In the industrial world, there are LOTS of converters--for just about everything (unfortunately, in my personal opinion--lots of them are not very good and not very robust). Use your preferred World Wide Web search engine and look for "proximity probe converters" and start there, and you will see some relevant searches with different equipment and terms and words you can also try searching with.

If I posted to an anonymous World Wide Web forum that my watch wasn't working and asking for help with repairing it, and you read the post, what would you say? HOW MANY questions would you have to ask to even begin providing useful information? Or would you just say, "Change the battery," without even knowing if the watch was electronic or mechanical (I wear an older self-winding watch). Would you ask if the display was working? (Remember my watch has hands--three of them.) Your question is similar in nature. There are several manufacturers of proximity vibration probes/sensors/pick-ups, and you didn't tell us ANYTHING about the ones you are trying to work with (without buying the proper card to interface with).

So, GET A CLUE and GIVE US A CLUE--and you will most likely be happy with the results. But we gotta have some basic information.

Or don't; it's your choice.

Thanks for your answer.
Here is my exact question:
We have a proximity probe which is installed to measure radial vibration of gas turbine shaft. The probe is connected to a proximity (model 3300 bentely nevada). Now our purpose is to convert the output of proximity to 4-20mA signal which is proportional to displacement. All in all, we aim to condition output signal of proximity for connecting to PLC. And our requirement is to find the suitable kind of converter or signal conditioner.
Thanks

 

Okay; so this is a step in the right direction.

I'm not exactly familiar with each of the Bently-Nevada systems but it seems that most of the cards used in the monitor racks have BNC output connectors on the front card edge which provide a buffered output which can be conditioned and fed to other controllers/systems as an analog signal. I'm not sure what the buffered output signal is (voltage or current) but I know it has been done. On some systems there was some kind of dropping resistor or something similar.

So, B-N radial vibration detection systems work like this: A proximity probe is mounted in very close proximity to the shaft itself. It detects minute changes in distance between the tip of the probe and the shaft. The proximity probe is connected to a device called a proximitor (using a "tuned" cable and proprietary connector). The proximitor is connected to a card in the monitor rack. There is another probe which detects rotational speed (RPM). The vibration card uses rotational speed along with changes in distance (gap) between the proximity probe and the shaft to determine magnitude of movement (vibration).

Again, most of the B-N cards I have seen have BNC connectors on the front edges of the cards, to which coaxial cables can be connected to obtain an analog signal relative to the vibration being measured. That signal has been successfully connected to controllers/systems of all types for many years. It's also used to get the signals into the B-N ADRE system....

You may also (probably will) find off-the-shelf converters specifically made for this application. You just need to use your preferred World Wide Web search engine to look for such converters (from buffered output to 4-20 mA, or 0-10 VDC or something similar). You may even find converters which can connect to proximity probes for the gap measurement, but you're going to need a very sophisticated controller and algorithm(s) and a speed signal to do vibration measurement without using the B-N rack.

Best of luck!

 

CSA is correct - B-N racks provide individual probes buffered o/p's. Many clients take this directly into PLC analogue cards for data processing. So why have something separate ?

Rockwell provide excellent Condition Monitoring equipment:
https://www.rockwellautomation.com/en-gb/products/hardware/allen-bradley/condition-monitoring.html

I worked with their vibration monitors of years gone by; very good kit but still a vibration monitor that have parameters similar to the B-N rack. Analogue o/p is voltage so unless you have specific reason to go 4-20ma I'd stick with voltage.
As stated they use" very sophisticated controller and algorithm(s)" which include FFT (fast fourier transform) and complex frequency filtering. To not set up (and /or not set up correctly) a vibration monitor means you will end up with streams of useless data fit for nothing.

 

oneye14,

vibration monitor means you will end up with streams of useless data fit for nothing.

The real fun starts when they begin to think they can STORE this useless data.