Cycle test noise ? Impulse test stand

[Davebones]

We have a impulse test stand that records data for testing . The technician showed me a 1 hz signal that has spikes on it when another test stand is running . The normal test the stand looks for pressure at around 2200 psi as the valve cycles . When the other stand ( located about 20 ft away ) is on the spike adds about 200 psi to the signal which is enough to cause the test to shut down since it is exceeding the parameters of the test . The two stands are fed from different busses but come from the same 480 volt service .The feed is conduit with ground wire . We added a building steel ground but no change . The stand is one complete package as the pumps and computer monitor were all buit together by one manufacture . We are looking at adding a driven ( supplemental ) ground rod at the stand . Know some of you engineers are really sharp so any suggestions would be appreciated ...

 

[gar]

150924-0751 EDT

I might be able to help, but I have no idea what you are talking about.

In all probability a ground rod will be of no use at either or both test stands.

You have two test stands. Each has a computer and some gaging equipment connected to its computer.

"We have a impulse test stand that records data for testing ."

What is an impulse test stand? What is being tested? How many sensors? What do the sensors measure? Pressure seems to be one measurement. What kind of pressure sensor, straingage, quartz, or other? What are the analog signal levels at the sensor output, and at the computer or A/D converter input? If you use a battery powered digital scope isolated from any connection to earth or EGC except at the probe input, with the probe tip and common leads as short as possible to look at the analog signal, is there any indication of the unwanted spike? This means no AC power input to the sxope, and the scope sitting on a dry cardboard box. These scope measurements are to try to locate where the noise is entering the measurement system.

"The normal test the stand looks for pressure at around 2200 psi as the valve cycles ."

What is the shape of a good waveform, sine wave, square pulse, or what? Show a picture of the waveform with and without the noise pulse.

Are the computers on the two test stations interconnected? Many other questions may help you find the origin of the problem.

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