EJW Posted December 16, 2007 Report Share Posted December 16, 2007 I am trying to take vibration measurements on our old test stands. The program i am writing in LV85 is to replace our outdated labwindows 5 program. I have a new pxi system to replace our outdated 286 machines. (dont laugh). We are taking vibration measurements with PCB accelerometers, typically 100mv/g and using an Althen VIB-RMS 5B module for signal conditioning. The origial system acquired this on an E series mf-DAQ, now i am using a 6221M. I am not familiar with C or labwindows and am unsure how they were calculating average g and peak g from the hardware i mentioned. I would assume (i know) that if i took my analog input multiplied it by 1000 (convert volts to millivolts) and divided it by the accelerometer's value (100mv/g) i would get g. That does not appear to be happening. Now i know the 5B is an RMS module and the accelerometer measures peak. I think i am missing something here that involves either the RMS value of sine (.707) or the square root of 2, or something. How do i calculate my peak g from an RMS value coming in and then how do i calculate an average g. FYI, no vibration toolkit, although it should not be needed as my signal conditioning ocurrs before my daq and not actually using a vibration daq. Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.