Does any one have any advice on trending rotating equipment condition with a SDT 170 ultrasonic meter and contact probe.
I am a new SDT user after several years using UWE gear and I do not know what amplification level I should set the meter at for consistent trending. I find the numerical (displayed) value varies widely with amplification level. I understand that I should adjust the amplification level to where there are no arrows(up or down).
For example: if I measure bearing "A" at amplification level 80 it is defening, so I lower the amplification down to 70,60, and then 50 and an arrow appears to raise the amplication level. So I raise the amplification level to 60 and there are no arrows,is this the correct/optimum level?
The problem I see is repeatability. Adjusting the amplification changes the displayed Db level so much that should another technician come along next time and measure bearing "A" with the amplification set at something other than the previous reading the values are not comparable. Should I just trend all points at the same amplification level?
I am about to set up routines for our condition monitoring department and would like to start off on the right track.
Any advice would be welcome.

Thanks

csmd

Hello CSMD,
it is a shame that you did not post your question a few weeks ago - I was giving a Level 1 training course in Truro!
There are several things you must keep in mind, the most important for trending being to have the right sensor working in the right mode.
If you are using the tri-band sensor, make sure that when you connect it that your instrument displays CONTACT -US across the top. If it does not, you are not in the ultrasound mode. Go into the menu and get to sensor options with the contact probe connected and select the bottom option US.

Please send me your email address and I will send you a detailed procedure for setting up your 170.

Best Regards,
Tom Murphy
tom@reliabilityteam.com

Thanks to Tom for the "reply" but unfortunately after contacting him several times the aforementioned detailed procedure for setting up the SDT 170 never materialized.
Incidentally, I believe Tom is employed by SDt and perhaps should be marked as a Vendor in this forum.

Hello Cosmo,

I'm Allan Rienstra from SDT North America, and make no bones about it, a VENDOR.

I am happy to discuss the proper set up for the broadband and magnetic contact probe you received with your SDT170 either on or off forum. You can contact me at 1-800-667-5325 or allan@sdtnorthamerica.com.

What I recommend for setting up the contact probe is the following:
1. Turn on the SDT170
2. Plug in the contact probe (depending on the type of probe some small changes to sdt170 manual set up may change... pending updated manual release)
3. If you are using broadband probe you will see "US Cable" in the top left corner of the LCD. Same if using the magnetic sensor because both these sensors use the same "ultrasound cable". If you are using the triband contact probe you will see "contact" to the left and either "SM", "M", or "US". Choose "US" for bearing measurements with this contact probe.
4. Choose if you want continuous values displayed or max value [Menu}settings}sensor options}Max Value} press enter to accept your choice].
5. With headphones on set the amplification to A=10. You will note that the UP chevron is on.
6. Put the contact probe on the bearing measurement point.
7. Adjust A=10 value upward until both chevrons are off. For the sake of this procedure let us say that your A=value is now 50.
8. If the signal is audible in the headset you may take a measurement by pressing the M+ button for 1-2 seconds. If the signal is too quiet to hear you may increase the A=value from 50 to 60. This should have a negligible affect on the dbuV reading but allow you to hear the signal more clearly. This is a step we engineered into the device to accomodate different hearing abilities in different inspectors.

Please contact me for further clarifications and/or questions.

Dear Gents,

I am an user of SDT170 and I have received SDT Level 1 and they recommend for contact probe to use :

- Filter SM (Slow Mech) for bearings less than 300 RPM.

- Filter M (Mechanical) for bearings 300-10.000 RPM.

- Filter US (ultrasound) for bearings RPM greater than 10.000 RPM.

In our experience filter SM is quite sensitive and we hear clearly some competing ultrasounds; US is less sensitive but it is not the recommendation that SDT gave yo us, so we are using to listen clearly sound from bearings magnetic probe.

On the other hand, could some of you explain to me which are the difference between filters SM, M, US in contact probe?

Best Regards,

Allen

Allan,

1. On my SDT170 I am using the probe with magnetic attachment. When this probe is attached the instrument won't give choices ( SM, M, US cable) as it does with a contact probe. The instrument in this case just displays "Ext. sensor".

Am I loosing any detection capability by doing that? Is magnetic probe in general better/worse then the contact probe in terms of measurement consistency ( assuming that flat washers are glued to the machine)?

2. In Menu}Settings}sensor option} Discov.fr.band the central frequency default is 38.4 kHZ. Is this the best number for bearing lubrication condition detection?

3. For bearing lubrication condition trending purposes which parameter is better: Continuous or Max?

Thanks,
David

David,

While you are waiting for a definitive answer, you could make comparison measurements with both handheld contact sensor and magnetic sensors. You might find that the magnetic Sensor produces a higher dB value and has a different audio characteristic. Your may have to measure a lot of bearings before getting any confidence in the measurements. Please post Some feedback on your trails and tribulations. I wish I had better results with the magnetic Sensor.

Walt