Accelerometer Maximum Cable Length
QUESTION
What is the maximum length allowed for an accelerometer cable?
ANSWER
With standard powering and sensors available in today's market, cables can generally be run to lengths of 200 feet without concern.
Cable routes much beyond 200 feet are common and rarely affect the measurement. However, we recommend that the sensor manufacturer be consulted to review the application, to determine the suitability of long cable runs. Long cable runs cause capacitive loading at high frequencies increasing the sensor's susceptibility to amplifier overload. The condition to be avoided is very long cables in the presence of high amplitude, high frequency signals when measuring low frequency, low amplitude signals.
As a rule of thumb most of the coax cables are 30 picofarads per foot; so a 100 ft cable would have a capacitance of 3000 picofarads. In such cases you would be able to take accurate readings up to 10 kHz before the frequency accuracy would be lost.
As you can see from this chart, even a 500 ft cable is okay as long as you only want to measure frequencies below 2000 Hz.
If you want to gain a better understanding of this subject please refer to the following link for an in-depth discussion of cable length www.pcb.com.
FAQ ID: 11650 Last Reviewed: 27 September 2005