Hi Roger, please help!

I am using DT800 in burst mode to read accelerometer data. Take excitation from 12V Serial Channel (have to, as need the other Sensor Supply to be 5 V, while the subject one needs min 8V). Output is connected as V to +/- connections.

The setup works fine with data values below 1000 mV. However, once the acceleration values exceed that level, the logged values go "sky high" (99999.9), for the duration of the high input and return back to "proper" values when input drops below 1000 mV.

I am trying to determine what causes this fault. Do I have a faulty sensor, is my DT800 setup incorrect or what? (NOTE! - I did not yet test the input on other channels, to see if there is a problem with just one of DT amplifiers).

I will be working on troubleshooting this problem, in a few days. Could you confirm that GL in burst mode is set at default 1V (as per your Tech Note)? Do you have any ideas, suggestions, to enlighten me re problem? I am a little confused about these 99999.9 readings!!

Another question! What is the accuracy of sensor power voltage outputs? (0, 5, 10V)

Hi Fred,

99999 is the over range error message. If you are using gain lock then select the next range up.

What is the maximum g output you are expecting? What is the Voltage output at that g level? If you are expecting say 1000 g and that has an output of 1 VDC at 1000 g then set the gain stage to the next level up (2 VDC) with the GL2V channel option.

Cheers,
Roger

That would explain it. The max will be around 1800 mV. i.e will use GL2V
I could not find the explanation for 99999 in the manual. Did not look too well, it seems.

Thanks!
Chris

Hi Chris,

There is a paragraph at the top right of page 197 that mentions the 99999 message. (You know like the fine print at the bottom of a contract that you need an electron microscope to read...)

Cheers,
Roger

Ah, yes. Found it! Thanks.

Mind you, I would probably still have a bit of a problem deciphering this statement. The Tech Note I mentioned above, talks about signal being clipped if GL is set too low. This is a little misleading! Anyway, all is working and the problem was exactly what you told me. Glad the sensor was OK. It costs close to 1K.

Ok, point taken.

I need to be more explicit in my descriptions when I write tech notes. (Yes, burst mode is one of mine)

Cheers,
Roger