Vibration Transmitter | 990-16-XX-01-CN 106M1675-01 | Bently Nevada

Technical Specifications

The 990 Vibration Transmitter is intended primarily for the original equipment manufacturers (OEMs) of centrifugal air compressors or small pumps, motors, or fans who prefer to provide a simple 4 to 20 mA proportional vibration signal as the input to their machinery control system. The transmitter is a two-wire, loop-powered device that accepts input from our 3300 NSv proximity probe and its matching extension cable (available in 5 m and 7 m system length options). 

Dynamic Signal and Third-Party Diagnostic Limitations (PROX OUT)

Dynamic signal sensitivity remains: Although the macroscopic range of 4-20 mA has been widened to 400 µm, the sensitivity of the raw microvolt AC waveform signal output from the panel BNC interface and terminal (PROX OUT) remains at 7.87 mV/µm (200 mV/mil).

Non-isolation warning: Because the PROX OUT of the 990 transmitter shares a common terminal (COM) with the negative terminal of the 4-20 mA, directly connecting a non-isolated AC-powered oscilloscope will disrupt the current distribution of the entire control loop. Bentley strongly recommends using the dedicated 990/991 Test Adapter for field signal acquisition.

Important Notes for Replacing an Old Transmitter

Confirm DCS/PLC Card Channel Range Settings: The maximum limit (20mA) of this analog channel (AI) must be changed internally within the DCS from the original 125µm or 200µm to 400µm (or 16 mils). Otherwise, the vibration values read by the system will be significantly reduced.

Confirm Sensor Compatibility: This model is also designed for the Bently Nevada 3300 NSv proximity probe system. Do not hardwire it to the standard 3300 XL 5mm/8mm probe, otherwise nonlinearity will occur.

Check Explosion-Proof Barrier (Safety Barrier): The suffix CN indicates that it is safe to enter explosion-proof areas. If this transmitter is installed in a hazardous area (such as Zone 1), the power supply circuit must be equipped with an explosion-proof barrier that meets the requirements of Bently Intrinsically Safety (IS) control drawings.

Technical FAQ

Q: How is the 4-20 mA loop current linearly mapped in 990-16-XX-01-CN 106M1675-01?

A: In the current loop output, 4 mA corresponds precisely to zero vibration, while 20 mA corresponds to the full-scale vibration level of 16 mils (400 µm).

Q: How should the "XX" cable length option be selected for the large measurement range 990-16-XX-01-CN 106M1675-01?

A: If the total nominal length of the proximity probe and extension cable is 5.0 meters, select 990-16-50-01-CN. If the total length is 7.0 meters, select 990-16-70-01-CN.

Q: How can high-frequency raw waveform data be acquired from 990-16-XX-01-CN 106M1675-01 while simultaneously using the 4-20 mA output?

A: The raw gap voltage and vibration signal can be accessed through the PROX OUT (dynamic buffered output) coaxial connector on the front of the module. This output can be connected directly to a portable diagnostic analyzer or the Bently Nevada System 1 platform to acquire the original signal with a nominal sensitivity of 200 mV/mil.

Q: What installation requirements are specified by the "01" option in 990-16-XX-01-CN 106M1675-01?

A: "01" indicates that the module is supplied with stainless-steel mounting clips and is designed for direct installation on a standard 35 mm DIN rail commonly used in industrial control cabinets.

Q: Are your products brand new?
A: Yes. We only supply 100% original and brand-new products. All items are sourced through authorized channels and have never been used or refurbished.

Q: Why can customers buy with confidence?
A: Because every product is backed by our 1-Year Warranty Guarantee of Quality, ensuring reliability, customer satisfaction, and long-term support after delivery.

Q: Do you provide international shipping?
A: Yes. We ship products to customers worldwide using reliable international logistics services such as EMS, DHL, UPS, and FedEx.

Trusted by 5,000+ plants worldwide |  Contact for more Bently Nevada spares: sales1@amikon.cn

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