DanDel,
the sensor is an accelerometer
www.omega.com part# ACC103
connected to a (battery-powered)
amplifier before entering the DAQ.
provides 0-10V output where
10mV = 1g acceleration.
at low frequencies, the noise comes
into the card as a steady 10-20mVAC
with lots of ugly spikes.
greets all,
don't know if i'm in the right group.
thought i purchased a 120/220V oscilloscope
(Tenma)
blindly plugged it into a 220V line and
it made a heartwrenching sound.
now all i get is two little dots in the middle of my screen. focus and intensity controls still work.. but thats about...
i appreciate all the feedback, thanks again.
not to be difficult, but my accelerometer is definitely picking this noise up. as *soon* as the accelerometer body touches my vibration table, my signal goes crazy.
perhaps the accelerometer is akin to my high-impedence meter?
two things happen...
the DAQ board can operate in either single-ended or differential mode. I'm set up in differential mode, as this should typically eliminate (reduce) ground noise. the problem is that (i think) i'm bringing 38VAC *directly* into the channel. differential mode benefits are nill here.
the...
my apologies.. caught an error.. the inverter is NOT outputting 380V/3Ph.. its output is 240V/3Ph.
that is, my inverter can only output 110% of line voltage (220V) ie.. 220x1.1=242V
inverter is supplying 3ph electric vibrator, DELTA connection (WYE connection limits my available RPM/Freq...
my first step tomorrow will be to bring in an earthground from outside. hopefully this will clear things up.
question: the main component in my DAQ setup is a vibrator/shaker to drive a vibration table. the vibrator is 3Ph/380V. it is delta-wired.
today i measured 38VAC between the motor...
re: faulty accelerometer
i've taken some steps to isolate the signal (better grounding).. i measured 38VAC between the shaker and the metal table its attached to. ie.. between motor ground and (any of) the 3phase (380V) feed lines. i'm not sure if this is normal or not, but i put a piece of...
greets all.
new here.. i apologize if i'm in the wrong
forum. but i was hoping someone could help.
in trying to isolate a little spurious noise from a data acquisition setup, i ended taking my voltmeter right to my wall socket. (the things we do at 3am)..
i'd like to know if what i've found...
interesting development in the past few hours:
(quick note: my accelerometer is screw-mounted to a small stainless steel block.. about 10mm x 10mm x 50mm. the block is then attached to my 'structure' with a C-clamp .. this way i can move the accelerometer anywhere i can get the clamp around)...
hello again. thanks for the quick response!
to clarify:
Omega hardware (www.omega.com) on Labview software (v6).
Omega Accelerometer ACC103 "laboratory accelerometer"
15grams, 10mV/g output up to 500g's.
the acc. is co-ax cabled to an ACC-PS1 powersupply,
which in turn is wired to...
Greets all.
I'm new here, looking for a few pointers.
am getting into some basic vibration measurement
and purchased an accelerometer (10mV/g) and a
DAQ board (100,000 samples/s).
my accelerometer is mounted on a electric vibrator
whose frequency i control via an inverter (0-150Hz;
0-9000 rpm)...
