Sudden spike in strain measurement

Hi!
I have a PXI 1062Q Chassis, 8108 controller (Windows OS), one PXI 4472 module(Slot 2) & two PXI 4331 modules(Slot 3 & Slot 5). The test scenario involves measurement from strain gauges mounted on a plate which is subject to some impact. But when I try to acquire strain data in the quarter bridge configuration from all the 16 channels at 100 K sampling rate, I find that there is a sudden spike in the data apart from the one observed due to the impact (Please refer attached pics). This spike is seen at exactly the same instant across all the channels. The following are the settings used for strain channel acquisition.
Acquisition Mode :Continuous Samples
Sampling Rate :100K
Samples to Read :10 K
Maximum Limit :1.5m
Minimum Limit : -1.5m
Strain Configuration :Quarter Bridge I
Voltage Excitation Source :Internal
Excitation Voltage :2.5V
Gage Resistance :120
Gage Factor :2
Note: Offset nulling & Shunt calibration are enabled (100K shunt resistor in R3 location)
The application was built using LabVIEW 2011 and DAQmx driver version 9.3.5
Can somebody please tell me what could be the possible reason behind this phenomenon?
Thanks in advance!
Shweta JP
Attachments:
Data with spike_1.png ‏34 KB
Data with spike_2.png ‏36 KB

Shweta_JP wrote:
Hey Lynn!
It's just a 1 sample spike in the positive & negative direction. Could an electrical transient result in such a small duration spike??
Shweta JP
EMC spikes could be of any length....
A good software spike filter is the median filter, here a filter rank of +-3 should do the job...
Looking at your picktures it seems that they appear in a close relation to your trigger ...
Crystal_ball_mode: You wrote impact test.... is there some sort of solenoid/relay/inductive release involved ? Without snubber they can be a source for such spikes....
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