The essential
The amplifier at the wheel digitizes the transducer signals. Everything specific to one transducer (its calibration, its recent zero values and its test setup) is stored in a removable smart sensor, not in the amplifier. The amplifier board itself is universal. If an amplifier fails, move the smart sensor to a spare amplifier of the same housing size and resume the test: the calibration moves with it.
Which amplifier goes with which interface box?
The D2 works with the CT2 interface box; the D3 and D3X work with the CT3. Any D2 amplifier can be upgraded to a D3 or a D3X.
- D2: CT2 interface box. Internal bi-axial accelerometer, X and Z.
- D3 and D3X: CT3 interface box. Internal tri-axial accelerometer, X, Y and Z.
- D3 and D3X differ by the slip ring model they pair with.
What is in the smart sensor?
Everything that belongs to the transducer. The smart sensor is a removable module held in the amplifier base by two #4-40 screws.
- All the calibration information of the transducer.
- Its recent zero values.
- The test setup selections.
How do you use a spare amplifier?
Move the smart sensor into a spare amplifier of the same housing size. Since the calibration is in the smart sensor, the spare gives the same accuracy without recalibration. Michigan Scientific and its sales and service partners keep spare amplifiers.
- Remove the two #4-40 screws of the smart sensor with a 3/32 in Allen wrench and take it out of the amplifier base.
- Fit the smart sensor into the spare amplifier the same way.
- Check that the serial number of the smart sensor matches that of the transducer.
- Mount the spare amplifier on the transducer and resume the test.
What do the internal accelerometers give?
Accelerations at the wheel, up to ± 100 g, low-pass filtered at 1 000 Hz (−3 dB). All amplifiers use the same MEMS accelerometer components, rated ± 120 g; the output is limited to ± 100 g.
- Available on both the CAN and the analog outputs.
- Internal to the amplifier: no separate sensor to mount, no extra cost.
To remember
- The calibration travels with the smart sensor, not with the amplifier.
- A spare amplifier of the same housing size restores the measurement without recalibration.
- Accelerations at the wheel come with the amplifier: X and Z on a D2; X, Y and Z on a D3 or D3X.