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Vibe-Rater

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Reply with quote  #1 
Hi all and particularly Rusty who I know has done this,

Today I tried / needed to do synchronous averaging test with the trigger on a large Yankee Dryer (3.6m / 12' diameter) which production wouldn't stop. And even if they did the surface temperatures would either make reflective tape fall off or lose its reflective properties.  So need to learn how to use a Speedvue without reflective tape as a tach.

In addition a shut is coming up and am trying to look for white optical reflective and heat resistant paint but not sure if I can find some in time.

Any suggestions anyone? Rusty / Oli / Sinski (PM4) you know the type of machine and probably others.

I have some other feelers out with locals here so I am hoping to find something. Even if I miss the shut I will be ready for next time. rgds.


OLi

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Reply with quote  #2 
Reflective maybe paint on the possibly a little colder "downstream" shaft if some is visible? Not that I tried. Maybe a inductive /eddy probe on something put on a bolt when stopped?
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Vibe-Rater

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Reply with quote  #3 
thanks Oli, they are emery'ing the Yankee so want to keep a bit of heat and pressure in it during that process. You are right, paint probably needs cold surface to dry, then OK for heat but without it going cold like nearly Sweden maybe paint option might not work but we will try.  See how we go. rgds
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Reply with quote  #4 
Not aware of any way to use a SpeedVue without tape. I don't think there is actually anything unique about the SpeedVue itself, other than perhaps the detector circuitry.. I think the reflected pulse train is simply fed by the detector to the meter as a voltage signal and an FFT is performed. (Now I'm curious if my 198F laser tach would work as a SpeedVue).

There are high temperature epoxies available which might secure a reflective target. I have seen some made of hard plastic on a few machines, but have never used anything like that myself. Take a look at:
http://www.britesidepanels.com/media/wysiwyg/products/3MColorsandFinishes.pdf

In transportation (referenced as DOT in the U.S.) they use retro-reflective tape, markers, etc. I think it will work with a tach - will try it this weekend. If a colored material will work (red or orange?) it would be easier to "find" on a spinning shaft.

But if you can secure a target, the SpeedVue is a handy field tach.

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James.

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Reply with quote  #5 
Hi Vibe, this is from some training when I was down under.

The primary function of the CSI 430 SpeedVue Laser Speed Sensor is to determine the speed (RPM) of a rotating shaft without the inconvenience of having to stop the shaft and apply reflective tape (as is required with infrared and other standard laser tachometers).
However there are occasions where it is desirable to use a SpeedVue like a conventional tachometer for phase measurements (such as for balancing).
It is possible to use the SpeedVue like a conventional tachometer when the shaft has a high-contrast once-per-revolution marker (such as a piece of reflective tape).
The SpeedVue is not a ‘TTL’ output device. It does not produce a standard 0-5 Volt DC pulse (like a CSI 404B Infrared Phototach). The voltage output by the SpeedVue is dependent upon a number of factors, including the relative contrast between the surface of the shaft and the phase marker, the size of the phase marker, the speed of the shaft, and the distance of the SpeedVue from the shaft. As such, the ‘trigger level’ of the tach pulse is different for different conditions, and must be manually determined. There is a technique for determining the appropriate trigger level which we call ‘Acquiring the Tach Pulse Waveform’.

Cheers
James
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Reply with quote  #6 
Cont.

A small piece of tape of 1 to 2 cm long is usually sufficient, but if you will have limited opportunity to stop and start the machine, you can pre-calculate the required length of tape for the application.
Under some circumstances it is possible to use a high-contrast feature on the shaft instead of reflective tape e.g., white paint, black electrical tape, keyway etc. However success and reliability is entirely dependent upon the amount of relative contrast between the feature and the shaft surface. Using retro-reflective tape ensures the highest possible contrast.
Position the SpeedVue and mounting bracket with a view of the reflective tape.
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Reply with quote  #7 
Cont.

Press the F1 button to go into Manual Analyze mode.

Press the F7 button to go to Tach set up.

Push the F12 button Set Defaults.

The SpeedVue laser beam should now be on. Flip open the lid (beam attenuator) and point the laser beam at the reflective tape on the shaft. Note: Avoid having the beam perpendicular to the surface of the shaft, as this reduces contrast between the reflective tape and the surface of the shaft.

Ensure cables are secured clear of the shaft and start the machine.

If you are lucky, the default trigger settings of the analyser may be adequate. To check, turn on Show RPM to see if the tach pulses are being detected.

If the tach pulses are not being detected at all, the Last RPM = displayed will be zero, and the Last Time = will counting up.
If the tach pulses are being detected intermittently/unreliably, then the Last RPM = will be unstable, and the Last Time = value will be unstable/non-zero.

If things are working correctly, the correct and stable speed will be displayed next to Last RPM =, and the Last Time = value will be zero and stable.

If you feel lucky, you can play around with the value of Set Trigger Level to see if you can get a reliable RPM value. Trigger levels somewhere between 0.2 and 2.0 Volts are a good starting point. However a better method is to actually choose a trigger level based on the actual pulse voltage.

If you have achieved a suitable trigger level, the Last RPM = will be stable and equal to the known speed of the shaft, and the Last Time = will be near zero and stable. As shown to the right.
Now that we have a reliable once-per-revolution tach pulse, the SpeedVue can be used for either speed measurements or phase measurements.
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Reply with quote  #8 
Hopefully that makes sense, I'm writing this on the mobile......
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Reply with quote  #9 
James, have never seen that info. It certainly doesn't come with the SpeedVue you when you purchase it. I have my tach sens set to 0.5 volts and the SpeedVue seems to work 99% of the time. Correct me if I'm wrong, but there are no settings in the meter which are particular to the SpeedVue… just the tach settings.

Be aware that CSI is not allowed to produce a laser tachometer due to a patent infringement settlement with TEC years ago. So of necessity they have to make the SpeedVue sound like it's not a tach.

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Reply with quote  #10 
Gotta love you guys being on the other side of the globe.  Means if its late for me you are still having your cornflakes.  I'll go and read it all now. rgds
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Reply with quote  #11 
Very good info James and Rusty, immense thanks. and you too Oli. And comments from others that may be to come too.

James, the other feeler I have out is AS from Croydon office (Rusty, AS is previous and recent third party distributor (but no longer) of CSI and considered CSI technical guru) and from another wise man he has written his own tech note about this.  That may very well be where you got all your info from James but i don't doubt your own ability for sure.  I'm sure I will nail it.  one thing, I will have to ask him if that is a tech note to share on forum or not considering he is the author not CSI for free distribution.  Will let you know accordingly.

Not sure if you know James but Croydon office is closing down and being moved to North Melbourne GE Office. Lots of changes, redundancies etc. Perhaps we take up private email and let you know more. rgds
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Reply with quote  #12 
Quote:
Originally Posted by RustyCas
James, have never seen that info. It certainly doesn't come with the SpeedVue you when you purchase it. I have my tach sens set to 0.5 volts and the SpeedVue seems to work 99% of the time. Correct me if I'm wrong, but there are no settings in the meter which are particular to the SpeedVue… just the tach settings.

Be aware that CSI is not allowed to produce a laser tachometer due to a patent infringement settlement with TEC years ago. So of necessity they have to make the SpeedVue sound like it's not a tach.


Hey Rusty,

Yep, spot on the only settings is for the tach, there is nothing in the meter specifically for the SpeedVue.

Cheers
James
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Reply with quote  #13 
Just need to determine if there is really anything all that special about the SpeedVue device. Will do that tomorrow afternoon.
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Reply with quote  #14 
I always believed that the only special was that it gives the raw reflected signal to be handled by FFT but I never got around to test either. Is the patent still valid? It may tell something. The normal average tacho do have a "trigger" circuit inside that only give a digital output that would trigger on the reflective material this may not have that so raw signal may be used.
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Reply with quote  #15 
I have good news, I managed to get it working.  During a shut client painted Yankee manhole bright white and today I managed to get Speedvue triggering in a stable fashion over about an hour. (65 rpm and lots of averages on a synchronous averaging test.

Speedvue is best thing since sliced bread.  Very successful and proved my point Yankee is barred.  rgds  ps and the key to get it working was described above. All in the tach settings, I was using 0.1 Volts.


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