Negative Voltage Accelerometer and Velocity Sensor Testing
Test negative-bias vibration sensors used with Bently Nevada monitoring systems using the AT-2040 proximity probe input and -24 V power output.
Testing Sensors That Standard IEPE Inputs Cannot Read
Some industrial vibration sensors use negative voltage power or a negative DC bias instead of standard positive IEPE excitation. These sensors should not be connected to a normal IEPE input. The AT-2040 supports these applications through its proximity probe terminal, which is designed to accept negative-voltage sensor signals.
The same terminal can also provide -24 Vdc power when sensor excitation is required, making the AT-2040 a practical tool for field testing, troubleshooting, and calibration verification.
AT-2040 Proximity Probe Connection
Negative-voltage sensors connect to the AT-2040 through the 3-pin proximity probe connector.
Common sensor families for this application include Bently Nevada 330400 / 330425 accelerometer sensors and 330500 velocity sensors. Always confirm the exact wiring, sensitivity, and power requirements from the sensor datasheet before testing. Negative-bias sensors should be connected to the AT-2040 proximity probe terminal, not the standard IEPE input.
330400 / 330425 Accelerometer Sensors
Negative-bias accelerometer sensors used for casing vibration measurements on rotating machinery. These sensors are commonly found in machinery protection and condition monitoring systems.
330500 Velocity Sensors
Negative-bias velocity sensors require the correct input path during calibration or functional testing. The AT-2040 proximity probe terminal accepts negative-voltage sensor signals for practical field verification.
Machinery Protection Sensor Systems
Verify spare sensors, troubleshoot questionable readings, and confirm sensor response before installation or during maintenance of critical rotating machinery.
AT-2040 Negative Voltage Connection
| AT-2040 Proximity Probe Terminal | Function |
|---|---|
|
SIG |
Sensor signal input |
|
COM |
Common / return |
|
-24 V |
Negative sensor power output |
How Testing Works with the AT-2040
- Mount the sensor to the AT-2040 shaker table.
- Connect the sensor to the proximity probe terminal useing the SIG / COM / -24 V wiring configuration.
- Apply the required vibration frequency and amplitude.
- Measure the sensor output through the negative-voltage input.
- Compare the result to the expected sensitivity.
- Save or document the result for verification records.
Common Applications
- Bently Nevada sensor verification
- Negative-bias accelerometer testing
- Velocity sensor testing
- Spare sensor inspection
- Field troubleshooting
- Turbine and compressor monitoring
- Motor, pump, and gearbox vibration checks
- Machinery protection system validation
Bently Nevada is a registered trademark of Bently Nevada, a Baker Hughes business. Agate Technology is not affiliated with, sponsored by, or endorsed by Baker Hughes or Bently Nevada. Product names and model numbers are used only to identify sensor compatibility and application use.
