It seems, that I'm having an issue with my Endevco 133.
If I measure the frequency response w/o any sensor attached, it has a big bump between 40Hz and 60Hz. Other than that it seems to work OK.
As I bought it used from eBay some time ago, I can't say anything about the conditions it has been used in or about it's age.
Ideas/ advice would be appreciated.
Best
Stephan
If I measure the frequency response w/o any sensor attached, it has a big bump between 40Hz and 60Hz. Other than that it seems to work OK.
As I bought it used from eBay some time ago, I can't say anything about the conditions it has been used in or about it's age.
Ideas/ advice would be appreciated.
Best
Stephan
The Endevco is an accelerometer amp. You should get a "flat" response, assuming no internal filters are engaged, driving it with a 1 nF cap in series. This issue drove me crazy until I got a service manual for a B&K vibration meter and found this direction. This is all I found on the 133 https://buy.endevco.com/contentstore/mktg/downloads/133_ds_082719.pdf
I'm using an Endevco Model 22 Accelerometer and the manual you found to set the parameters. Seems to work fine!
As the bump is around 50Hz, my assumption/ fear is that the 133 might have an issue with it's internal power supply.
That 1nF cap - where exactly should that be put? In series with the accelerometer?
As the bump is around 50Hz, my assumption/ fear is that the 133 might have an issue with it's internal power supply.
That 1nF cap - where exactly should that be put? In series with the accelerometer?