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Signal conditioner output scaling

Question

I have an Endevco model 136 Signal Conditioner and I am using a transducer that has a very low sensitivity of 2.847 microvolts per g. I am trying to enter this number into the output scaling of the 136, but I see I have to round it to 3 microvolts per g. It there a way I can enter the precise value?

Answer

Yes. The Endevco 133 and 136 signal conditioners are designed for ease of entry of the accelerometer sensitivity and the desired output specified in millivolts per engineering unit. In cases where very low sensitivity transducers are used, such as high g shock accelerometers the user must either round off the sensitivity, or perform some calculations to enter the precise value. By using the following step-by-step procedure for a sensor that has a sensitivity of 2.847 microvolts per engineering unit (psi, g, etc) and has a full scale output (FSO) of 60,000 g, precise values can be entered into the signal conditioner.

  • Determine the desired full scale output from the 133/136. Assume that we are using a DAQ that has a 10 Volt input, thus we will use 10 Volts as our desired output level from the signal conditioner.
  • Calculate the gain required to obtain 10 VoltsSensor's full scale output =
    60,000 g X .002847 mV = 170.82 mV
  • Determine "Output Scaling":
    Gain X Sensitivity = 58.54 X 0.002847 = 0.167
  • Output Scaling = 0.167 X 1000 = 167
  • Multiply the sensors sensitivity by 1000 and enter 2.847 into the 133/136 as sensor sensitivity
  • Enter 167 into the Output Scaling section of the 133/136