I think this has had a little discussion before but I have a few questions to ask about it again.

You guys/girls who use the 2130, do you have much of a problem with the ski slope, especially on the slower speed stuff while using a low Fmax and a low cutoff for the lowend?

By slow speed I mean somewhere around .5 to 2 Hz running speed and an Fmax of 200 Hz with the default lowend?

Second question:

How many of you use the Wilcoxon 793 transducer with the 2130? Do you have the same problem with the ski slope using the 793 as compared to the standard smaller size transducer such as the one from CSI (do not know what the number is)? I used the 793 with the 2120 when I was working for my former employer inhouse and never had the ski slope problem with the 2120, 2115 or 2110, so I am wondering if the 793 is a better choice for the 2130 since many of my clients are having constant complaints about the repeated problem of the ski slope. Settling out time seems to have very little effect of having and not having the problem.

BTW it doesn't make very much, if any, difference whether analog or digital is used.

This message has been edited. Last edited by: Ralph Stewart,

remember the 2130 has 2 types of input connections, turck and 2120 style... from what I understand the connection may cause differences..just a thought

We've had similar problems with this. We found out that some of the 2130's were sold with a defective cable (the one with the turck fitting). The defective cable can cause the ski-slope.

I'm sure this isn't Ralph's problem, but it reminds me of a problem one of my customers had a few years ago.

A Reliability Engineer at a nearby plant called me asking about a 'ski-slope' problem he was having with his dataPac. I didn't really have an answer, so after we were certain everything was setup correctly I told him to try a different accelerometer and cable and if that didn't work to send his meter off for calibration/repair.

After buying a new accelerometer and cable and sending the unit off for calibration he called me back with the same problem asking if I could come over and have a look. When I got to the plant he showed me 18 months worth of data with your typical ski-slope. When we went out into the plant I was watching him collect his data and as he watched the magnitude and pushed the store button he then very quickly pulled the accelerometer off the machine and waited for the next measurement. Mind you, this is very intelligent guy with an Engineering degree and a lot of common sense. It was very difficult to tell him that he had to wait for the measurement to complete BEFORE he removed the accelerometer from the machine .

Sorry, I hope I did't offend Ralph.
We have a continuing problem with bad data, sometimes it's the equipment. However, most of the time it turns out to be the guy pushing the button.

Ralph, I rarely see any ski slope in my saved data collected with the 2130, the bad data can be seen while being collected with the waveform display. The 2130 set up using the quad view allows you to monitor spectrum and waveform of both channels while the data is collected, as soon as the waveform shows any data you can tell if the accel has settled down or not. If you do not have a good waveform showing you need to take the data over, if you still get a bad waveform check your cable.
Last week I had a cable start acting up when in a certain position, saw this immediately in the waveform.

Scott

fisher1,
Man! you didn't offend me.

MikeH,

Do you have a 2130 yet? Are you still using the 793 transducer, other than on the wired out stuff?

All,

Are any of you using the 793 with the 2130 and/or a strong magnet. This ski slope problem is about to "get to" some of my clients. All wait for the transducer to settle down but like I said, this doesn't seem to help all that much.

Could it be the 2130 is so fast that it is actually messing up rather than being beneficial? I have watched during their data collection and nothing moves, everything seems ok, it seems to just happen when it wants to.

Ralph,

I am using a 793 and a strong (95lb pull) magnet on a 2130. We did have some ski slope issues, mainly with the small CSI Accels, but haven't had any problems with the present set up. I have also gotten away from the turk connector and use the 628A (25pin) dual channel adapter instead.

Good luck,
Dennis

Thanks Dennis.

I am thinking of testing a couple of my clients using the 793 and a 90 pound magnet. Just needed to hear some of you guys say they have better luck with the ski slope issue with the 793 and a strong magnet. I hope to try the setup next week at my closest customer's site. Where did you get your magnet from?

MikeH,

The large magnet you use at your place, do you know where they were bought?

Anyone else out there using the setup Dennis is using? If so, what kind of luck are you having?

Ralph - I looked at specs on Wilcoxon's web site for the 793L but didn't find setling time but, as I recall, the settling time for the 793 is rather long; I've found that I've needed as long as 10 seconds for some applications. Any intermitent cable opens or shorts or impacts that saturate the sensor preamp effectively reset the beginning of the settling period. Saturation occurs at roughly +/- 5G

I had three new 2130's right out of the box with ski slopes. Turned out to be the cable with turk connection. We used the straight cable and 628A dual channel adapter that came with the analyzer, solved the problem.

Ralph,
going to 2130's, gave info not on experience yet, but from everyone I talked to that had ski slope problems.. most left the turck connections.

line of magnets I use in attached file

magnets.pdf (230 Kb, 50 downloads)

Ralph,

I have struggled with this also. In my experience, it seems to be less dependent on speed and more on energy level in the WF; if WF pk is < ~.1 G's (more likely in slow speed applications) the WF becomes erratic and slope is present. Doesn't seem to matter how long it is allowed to settle or how still the cable is held.

I also got shed of the turck connector.

quote:

line of magnets I use in attached file

Thanks Mike.

quote:

Doesn't seem to matter how long it is allowed to settle or how still the cable is held.

Thanks Micheal S

quote:

I've found that I've needed as long as 10 seconds for some applications.

Thanks Duncan. I hope to try the 793 this week at one of my clients. What does the "L" in 793 stand for?

All,

I do not know if the "TURCK" connection is being used by these guys or not. I need to check on that. I do know they have to take the data over and over sometimes to get a good signal and then sometimes it never gives the really good signal. I have counted the settling time and all of them appear to wait more than seems would be required.

quote:

What does the "L" in 793 stand for?

Low Frequency

Dave

quote:

Low Frequency

Thanks Dave.

Never used one of those. Never thought I needed anything other than the standard general purpose 793. Most of the slow stuff I use to collect at my in house job was 20 rpm and higher, some a little slower, but not many and the GP 793 worked well there also.

Ralph,

I am using the CTC MH115-2A magnets (listed in the PDF attached by MikeH).

Dennis,

Ralph,
The 2120 did not display the first two LOR.
This is not how the 2130 does it. My CSI rep.
could not tell me how the 2130 did this.I have now retired and gone home but would like to know what you found.

turck connector on 2130
wilcoxon 799 accel
50 and 100 Fmax
no ski slope

quote:

turck connector on 2130
wilcoxon 799 accel
50 and 100 Fmax
no ski slope

Jonesy,

Sound goods, but I am sort of afraid of the connector. What about your magnet, heavy, medium or light pull and large diameter or the smaller one like comes on a small transducer?