Crossbow CXL accelerometer and BNC 2140 connection

[Zenz]

I wish to carry out some vibration testing using crossbow accelerometers with a DAQ BNC 2140 for further analysis. Unfortunately, the acccelerometer does not come with a compatible BNC connector. From the spec sheet, 3 pins are basically needed for signal transmission, 5Vdc power supply line(equivalent to 4mA), GRD and AZout for signal. The BNC is capable of supplying 4mA to any ICP accelerometer. It will be grateful if someone could let me soon how to connect the accelerometer 3 pins to the BNC +ve and -ve terminal while keeping the ICP of BNC board fully functional. Please kindly let me if any voltage regulation required if this is possible. Thanks in advance.

[Dustin_W]

The excitation provided by the 2140 is a constant current source. You might want to double check the specifications of your accelerometer to make sure that is applicable. I took a look at the specs for a couple Crossbow CXL modules, and it looked like they required a constant voltage supply rather than current (you cannot replace one with the other).

That said, the way to do a 2-wire connection to accelerometers is for the excitation to be on the same line as the signal - that is tie the supply line to the AZout. And flip the switch on the 2140 to turn the IEPE switch on.

If you do require a voltage supply seperately, just connect the GND and AZout - GND goes to the shell of the BNC, AZout to the center pin. In this case seperatly connect your power supply.


Hope this helps!

[barkera]

Zenz, I too have similar Crossbow accelerometers. Did the BNC connection work out for you? I suppose the other alternative is to use a different accelerometer with IEPE BNC connectors.