FAQ

Do I need anything else besides this transmitter to measure vibration?

Yes. The 990 transmitter requires a compatible 3300 NSv proximity probe + extension cable. The probe provides the physical sensing (non-contacting measurement of shaft/target displacement), and the transmitter conditions this probe signal into the 4–20 mA output. Without the

proper probe and cable, the transmitter cannot function.

What kind of machinery / applications is this transmitter suited for?

Because of its compact size, 2-wire design, and 4–20 mA analogue output, 990-series transmitters (including 990-10-XX-01-05) are

well suited for smaller rotating machinery like centrifugal air compressors, small pumps, motors, fans, or any application where

continuous simple vibration amplitude monitoring is required rather than detailed spectrum analysis.They’re often

 used by OEMs or in OEM-style installations where space is limited, simplicity is prioritized,

and outputs need to feed straightforward control/alarm systems (DCS, PLC, SCADA, etc.) rather

 than dedicated vibration analyzers.

How reliable is the output / what’s the accuracy?

According to Bently’s datasheet, the 990 transmitter provides ±1.5% accuracy over the specified full-scale range

for the 4–20 mA output when properly installed with a compatible probe and

within recommended conditions.