990 Vibration Transmitter
Datasheet

Bently Nevada Machinery Condition Monitoring141612 Rev. U

Description
The 990 Vibration Transmitter is intended primarily for theoriginal equipment manufacturers (OEMs) of centrifugal air
compressors or small pumps, motors, or fans who prefer toprovide 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).
The transmitter conditions the signal into appropriate peakto-peak vibration amplitude engineering units, and provides
this value as a proportional 4 to 20 mA industry-standard
signal as the input to the control system where machinery
protection alarming and logic occurs†.
The 990 transmitter provides the following notable features:
l

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Integrated Proximitor Sensor requires no external unit
Non-isolated "PROX OUT" and "COM" terminals plus a
coaxial connector to provide a dynamic vibration andgap voltage signal output for diagnostics‡.
Non-interacting zero and span potentiometers under
the Transmitter label supports loop adjustment.
Test Input pin for quick verification of loop signal output,
using a function generator as the input.
A Not OK/Signal Defeat circuit prevents high outputs or
false alarms due to a faulty proximity probe or loose
connection.
Choice of DIN-rail clips or bulkhead mounting screws
as standard options simplifies mounting.

990 Vibration Transmitter
Datasheetl141612 Rev. U

isolation between test equipment and the loop
signal, and ensure that the installation
maintains machinery protection integrity.

Potted construction for high humidity (upto 100% condensing) environments.
Compatibility with 3300 NSv proximity
probe allows transducer installation insmall areas with minimal clearance,
typical of centrifugal air compressors.

Notes† Vibration transmitters have many limitations

when compared to a continuous vibration
monitoring system. They are a practicalsolution in some applications for measuring
general vibration levels and are a valuable tool
for overall vibration trending. However, they
provide limited capability for machinery
diagnostics using the vibration signal and do
not capture dynamic vibration signals (used for
diagnostics) in the event of a vibration alarm.
While the transmitter is capable of peak
vibration alarming and non-OK checking, the4-20 mA signal cannot be used to determine
the phase of vibration, and monitor functions
such as gap alarms, phase alarms, Timed OK
channel defeat, Danger Bypass, and Trip
Multiply cannot be used. In addition, PLCs
attached to the vibration transmitter can only
provide peak-to-peak trending data and are
not suitable for plant-wide diagnostic systems
such as System 1 or Rule Paks.
‡ The 990 Vibration Transmitter's "Prox Out"coaxial connector provides a non-isolated
dynamic transducer signal for machinery
diagnostics. You can connect this signal
directly to battery-powered or isolated test
equipment to diagnose machinery problems.
However, since the "PROX OUT" signal is not
isolated from the 4 to 20 mA loop signal, aninterface is available (and strongly
recommended) for signal isolation. The
990/991 Test Adapter conditions the 990
Transmitter's "PROX OUT" signal for use with acpowered test equipment. It also inverts andisolates the 990's transducer signal, making itsuitable for equipment such as oscilloscopes
and analyzers, and preserving industrystandard conventions for signal polarity. We
strongly recommend the use of this test
adapter for all applications to maintain

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990 Vibration Transmitter
Datasheet

141612 Rev. U

Specifications
Unless otherwise noted, the following
specifications apply at +22°C (+72°F) using a
3300 NSv Probe and Extension Cable, and an
AISI 4140 steel target.
These specifications also apply to 990
with modifications 147202-01 (RMOD
4140 3300XL 8MM 5M) and 165335-01(MOD 4140 3300 XL 8MM 9M).

Electrical
Input

Accepts 1 non-contacting 3300
NSv Proximity Probe andextension cable.

Power

Requires +12 to +35 Vdc input at
the transmitter terminal.

4 to 20 mA
signal output

4 to 20 mAdc over specified fullscale range in 2-wireconfiguration.

Within ±1.5% over specified fullscale range. Accuracy is rated
from the TEST signal input to the
4 to 20 mA loop
voltage measured across a 250 Ω
accuracy
loop resistance. The ±1.5% error isin addition to the Prox Out
Incremental Scale Factor.

Probe gap

Maximum loop
resistance

Probe must be gapped between
0.5 and 1.75 mm (20 and 55 mils)from target to ensure full scale
range.
1,000 Ω including cable at 35 Vdc.

Current limiting 23 mA typical.
Zero and span

Non-interacting external
adjustments.

NOT OK/signal
defeatSignal output will go to less than
3.6 mA within 100 µs after a Not
OK condition occurs. Signal
output is restored within 2-3
seconds after the Not OK
condition is removed.

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Power-up
inhibit

Signal output stays at less than
3.6 mA (NOT OK) for 2 to 3
seconds after power is applied.
The purpose is to signal that thedevice is not yet ready. Transients
may be observed when device
goes O.K.

Proximitor
sensor output

Compatible with ungrounded,
portable test equipment. Whenusing grounded, ac-powered test
equipment, use the 122115-01 Test
Adapter for signal isolation.

Outputimpedance

Prox Out has a 10 kΩ output
impedance calibrated for a 10 MΩ
load.

Prox out linear
range

1.4 mm (55 mils). Begins atapproximately 0.25 mm (10 mils)from target surface.

Prox Outincremental
scale factor

7.87 mV/µm (200 mV/mil) ±6.5%
typical includinginterchangeability errors whenmeasured in increments of 0.25
mm (10 mils) over the linear
range using a flat 30 mm (1.2
inch) target. Worst case 7.87
mV/µm ±10%. Typical Noise Level:
50 mV/pp.

Temperaturestability

Incremental scale factor remains
within ±10% of 7.87 mV/µm (200mV/mil) from 0°C to +70°C (+32°F
to +158°F).

Frequency
response

5 Hz to 6,000 Hz +0, 3 dB.

Minimumtarget size

9.5 mm (0.375 in) diameter.

Leadwire
lengthMaximum for Proximitor Sensor
Output (BNC connector),
maximum cable distance is 3
meters (10 feet).

NonHazardous,
Zone 2 or Div 2
Hazardous
area locations

Power Supply: 28 V

990 Vibration Transmitter
Datasheet

141612 Rev. U

Environmental Limits
Transmitter Temperature

Probe
Case
ThreadMaximum Length of Thread
Engagement

Operatingtemperature-35°C to +85°C(-31°F to +185°F)

M8x1

12 mm

Storagetemperature-52°C to +100°C(-62°F to +212°F).

M10x1

15 mm

Maximum thread engagement
lengths are per the industry standardof 1.5 times the nominal thread
diameter. A fit class matching that of
the external probe thread is assumed
for all internal threads. Applications
with thread engagement lengths
exceeding the values in the table
above may exhibit binding during
installation. Contact your Bently
Nevada representative if you require
probe thread engagement lengths
exceeding the values above. Bently
Nevada does not replace proximity
probes under warranty due toexcessive thread engagement
lengths.

Probe Temperature
Operatingtemperature-52°C to +177°C(-62°F to +351°F)

Storagetemperature-52°C to +177°C(-62°F to +351°F)

Relative
humidity

100% condensing, non-submerged,
with protection of coaxial
connectors.

MechanicalTransducer
tip material

Polyphenylene sulfide (PPS).

Transducer
casematerial

AISI 303 or 304 Stainless Steel (SST).

Probe Cable75Ω coaxial, fluoroethylene
propylene (FEP) insulated.

Cable armor(optional)

Flexible AISI 302 SST with optional
FEP outer jacket.

Tensilestrength222 N (50 lbf) probe case to probe
lead, maximum.

Transmitter
weight0.43 kg (0.9 lbm).

Total systemweight0.82 kg (1.8 lbm) typical.

When drilling and tapping amounting hole for a 1/4-28 probe, a#3 or larger tap drill isrecommended.

Thread Engagement Limits
Probe
Case
ThreadMaximum Length of Thread
Engagement

1/4-280.375 in

3/8-240.563 in

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990 Vibration Transmitter
Datasheet

141612 Rev. U

Compliance and Certifications
FCC
This device complies with part 15 of the
FCC Rules. Operation is subject to thefollowing two conditions:llThis device may not cause harmfulinterference.
This device must accept any
interference received, includinginterference that may cause
undesired operation.

EMC
EN 61000-6-2
EN 61000-6-4
EMC Directive 2014/30/EU

ATEX
ATEX Directive 2014/34/EU

RoHS
RoHS Directive 2011/65/EU

Maritime
ABS 2009 Steel Vessels Rules
1-1-4/7.7,4-8-3/1.11.1,4-9-7/13

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990 Vibration Transmitter
Datasheet

141612 Rev. U

Hazardous Area Approvals
For the detailed listing of country andproduct-specific approvals, refer tothe Approvals Quick Reference Guide(108M1756).
For additional technicaldocumentation, please log in to
bntechsupport.com and access the
Bently Nevada Media Library.

cNRTLusClass I, Div 2Groups A, B, C, D
T5@ Ta [+85°C, Type 4]
Installed per Drawing 128838

ATEX/IECEx

II 1 GEx ia IIC T4 Ga
T4 @ Ta = -35°C to +85°C

II 3 GEx nA IIC T4 Gc
T4 @ Ta= -35 ˚C to + 85˚C

Entity Parameters
Zone 2
Power Supply: 28 V

Zone 0/1
Terminal
Terminal
blocks E3-E4
blocks E1-E2
and“Power supply
connector J2
4-20 mA”"Proximitor"

Connector J3"Probe"Ui [28 V]

Uo [28 V]

Uo [28 V]

Ii [120 mA]

Io [6 mA]

Io [100 mA]

6/17

Pi [0.84 W]

Po [0.17 W]

Po [0.8 W]

Ci [20 nF]

Co [80 nF]

Co [27.3 nF]

Li [10 μH]

Lo [1 H]Lo [5.3 mH]

990 Vibration Transmitter
Datasheet

141612 Rev. U

3300 NSv Proximity Probes,
Standard

Ordering Information

Part Number-AA-BB-CC-DD-EE

For the detailed listing of country andproduct-specific approvals, refer tothe Approvals Quick Reference Guide(108M1756).
For additional technicaldocumentation, please log in to
bntechsupport.com and access the
Bently Nevada Media Library.

990-AA-BB-CC-DD

3309013300 NSv Probe, 1/4-28 UNF
thread, without armor.

3309023300 NSv Probe, 1/4-28 UNF
thread, with armor.

3309083300 NSv Probe, 3/8-24 UNF
thread, without armor.

3309093300 NSv Probe, 3/8-24 UNF
thread, with armor.

A:Unthreaded Length Option

A: Full-scale Option

Unthreaded length must be at least
0.7 inches less than the case length.

04

0-4 mils pp (0-100 μm pp)

05

0-5 mils pp (0-125 μm pp)

08

0-8 mils pp (0-200 μm pp)

Order in increments of 0.1 in10

0-10 mils pp (0-250 μm pp)

Length configurations

B: System Length Option

Minimum length: 0 in

50

5.0 meters (16.4 feet)

Maximum length: 9.2 in

70

7.0 meters (23.0 feet)

Example: 04 = 0.4 in

C: Mounting Option

B: Case Length Option

01

35 mm DIN rail clips

Order in increments of 0.1 in02

Bulkhead screws

Minimum length: 0.8 in

03

DIN clips and screws

Maximum length: 9.9 in

D:Agency Approval Option

Example: 35 = 3.5 in

00

Not required

C: Total Length Option

01

CSA Division 205

0.5 meter (1.67 feet)

05

CSA Division 2, ATEX Zone 0, ATEX
Zone 2 and includes ABS
maritime approval

10

1.0 meter (3.25 feet)50

5.0 meters (16.4 feet)70

7.0 meters (23 feet)

D: Connector Option

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990 Vibration Transmitter
Datasheet

141612 Rev. U

01

Miniature coaxial ClickLoc
connector with connector
protector, standard cable

Order in increments of 10 mm

02

Miniature coaxial ClickLoc
connector, standard cable

Maximum length: 250 mm

11

Miniature coaxial ClickLoc
connector with connector
protector, FluidLoc cable

12

Minimum length: 20 mm

Example: 25 = 250 mm
C: Total Length Option

Miniature coaxial ClickLoc
connector, FluidLoc cable

E: Agency Approval Option00

Not required

05

Multiple Approvals (CSA NRTL/C
and BASEEFA/CENELEC, which
includes CSA Division 2)05

0.5 meter (1.67 feet)10

1.0 meter (3.25 feet)50

5.0 meters (16.4 feet)70

7.0 meters (23 feet)

D: Connector Option

3300 NSv Probes, Metric01

Miniature coaxial ClickLoc
connector with connector
protector, standard cable

02

Miniature coaxial ClickLoc
connector, standard cable

11

Miniature coaxial ClickLoc
connector with connector
protector, FluidLoc cable
Miniature coaxial ClickLoc
connector attached, FluidLoc
cable

Part Number-AA-BB-CC-DD-EE
3309033300 NSv Probe, M8 x 1 thread,
without armor.

3309043300 NSv Probe, M8 x 1 thread,with armor.

123309053300 NSv Probe, M10 x 1 thread,
without armor.

E: Agency Approval Option

3309103300 NSv Probe, M10 x 1 thread,with armor.

A: Unthreaded Length Option
Unthreaded length must be at least
20 mm less than the case length.
Order in increments of 10 mm
Minimum length: 0 mm
Maximum length: 230 mm
Example 06 = 60 mm
B: Case Length Option

8/17

00

Not required

05

Multiple Approvals (CSA NRTL/C
and BASEEFA/CENELEC, which
includes CSA Division 2)

990 Vibration Transmitter
Datasheet

141612 Rev. U

3300 NSv Reverse Mount Probe
330906-02-12-CC-DD-EE 3/8-24 UNF
threads
330907-05-30-CC-DD-EE M10 x 1 UNF
threads
C: Total Length Option

01

With FEP covered stainless steel
armor

02

With stainless steel armor

03

Without stainless steel armor,
with connector protector

04

With FEP covered stainless steelarmor and connector protector

05

With stainless steel armor andconnector protector05

0.5 meter (1.67 feet)10

1.0 meter (3.25 feet)

C: Agency Approval Option

50

5.0 meters (16.4 feet)00

Not Required

70

7.0 meters (23 feet)

05

Multiple Approvals (CSA NRTL/C
and BASEEFA/CENELEC (which
includes CSA Division 2)

D: Connector Option
02

Miniature coaxial ClickLoc
connector, standard cable

12

Miniature coaxial ClickLoc
connector attached, FluidLoc
cable

E: Agency Approval Option00

Not required

05

Multiple Approvals (CSA NRTL/C
and BASEEFA/CENELEC, which
includes CSA Division 2)

Extension Cable
330930-AAA-BB-CC
A: Cable Length Option
040

4.0 meters (13.1 feet)045

4.5 meters (14.8 feet)

060

6.0 meters (19.7 feet)065

6.5 meters (21.3 feet)

B Armor Option
00

Without stainless steel armor

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990 Vibration Transmitter
Datasheet

141612 Rev. U

Accessories

990/991 Test Adapter Accessories

990/991 Test Adapter. Package
includes: 990/991 Test Adapter,
9V battery, Universal AC
Adapter, Power Cord (North
American), User Guide and Soft
Carrying Case.
The 990/991 Test Adapter inverts
and isolates the PROX OUT
signal from the 990 Transmitterso that you can connect 990
Transmitters to AC-powered
diagnostic equipment. The
Adapter modifies the PROX OUT
signal so that it matches ourstandard Proximitor sensor
signals by performing thesefunctions:l122115-01

l

l

l

l

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Coaxial Cable Kit. Includes 4
cables with length of 1.5 meters (5feet) each.

02211505

Single coaxial cable with length of
1.5 meters (5 feet).

990/991 Test Adapter Spare Parts

Shifts the phase of the
PROX OUT signal by 180ºby changing the voltage
from positive to negative
Shifts the phase of the
PROX OUT signal by 180ºby changing the voltage
from positive to negative
Shifts the phase of the
PROX OUT signal by 180ºby changing the voltage
from positive to negative

01810700

Battery (9 volt alkaline).

02270056

AC adapter. Has universal AC
input to 9 volts DC output. Input
is 108 to 132 Vac with 120 Vac
nominal, or 207 to 253 Vac with
240 Vac nominal.

02198937

Power cord (for North American
AC power outlet).

123133

990 Test Adapter User Guide

Probe and Transmitter Accessories

The 990/991 Test Adapter
provides the following benefits:l123266-01

Small size and weight for
portable operation
Battery or AC adapter
power options
Automatic shutoff circuitthat powers down the unit
when the battery is low
2 channels, so that you
can display an orbit for XY
probe configurations.

02173006

Bulk cable (specify length in feet).
1.0 mm2 (18 AWG), 2-conductor,
twisted, shielded cable used forthe 4 to 20 mA loop. Also used for
the PROX OUT signal on the 990
Transmitter's terminal strip.

123655990/991 Transmitter System
Installation User Guide

Cable Connector Kit. Package
Includes 1 set of 75 Ω miniature
male and female connectors,
330153-05
shrink tubing and 3300 Isolator
Seal for protection of coaxial
connectors.

163356

10/17

Connector Crimp Tool Kit.
Includes one set of 75 Ω ClickLoc
inserts and connector installation
instructions. Supplied withcarrying case.

990 Vibration Transmitter
Datasheet

330951-01

990 Mounting Screws (spares).
Contains 4 screws.

284726

DIN rail mounting kit. Installed on
the 990 Transmitter to allow
mounting on 35 mm DIN rail.

141612 Rev. U

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990 Vibration Transmitter
Datasheet

141612 Rev. U

Graphs and Figures
All dimensions shown in millimeters (inches) unless noted otherwise

1. Mounting holes, 5.8 mm (0.23 in) diameter, 4 places
2. Bulkhead mount holes, 4 each. 6-32 x 1.326 screws
provided when mounting option specified
Figure 1: 990 Vibration Transmitter Dimensions (top view)

1. 35mm DIN rail DIN mount clips (when DIN rail mounting is
specified)Figure 2: 990 Vibration Transmitter Dimensions (side view)

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990 Vibration Transmitter
Datasheet

141612 Rev. U

1. Probe tip, 5.26 mm (0.207 in) maximum diameter
2. Hexagonal nut
3. Case Thread
4. Wrench flats
5. 75Ω cable, 2.8 mm (0.11 in ) maximum outside diameter,
7.6 mm (0.30 in) maximum outside diameter of armor
6. Miniature male coaxial connector, 7.23 mm (0.285 in)maximum outside diameter “D”
7. Unthreaded length “A”
8. Case length “B”
9. 2.92 mm (0.115 in) maximum
10. Total length “C”, +30%, -0%
Figure 3: 3300 NSv Proximity Probes, Standard Mount

Standard mounts
Available Probes
330901, 1/4-28 UNF-2A, without armor
1/4-28 UNF thread probes
330902, 1/4-28 UNF-2A, with armor
330903, M8x1 thread, without armor
M8x1 thread probes
330904, M8x1 thread, with armor
330905, M10x1 thread, without armor
3/8-28 UNF thread probes
330908, 3/8-24 UNF-2A, without armor
330909, 3/8-24 UNF-2A, with armor
M10x1 thread probes

13/17

Supplied with these wrench flats
7/16-inch lock nut and 7/32 inch
13-mm lock nut and 7 mm.
9/16-inch lock nut and 5/16-inch.
17-mm lock nut and 8 mm.

990 Vibration Transmitter
Datasheet

141612 Rev. U

1.
2.
3.
4.

12 mm (0.49 in) maximum diameter
36.3 mm (1.43 in) maximum
51.1 mm (2.01 in) maximum
Connector protector (fluorosilicone material)

Figure 4: Installed Connector Protectors

1.
2.
3.
4.
5.
6.
7.

Probe tip, 5.26 mm (0.207 in) maximum diameter
Hexagonal nut
Case thread75Ω cable, 2.8 mm (0.11 in) outside diameter
5.08 mm (0.20 in)
Unthreaded case length “A”, 5.08 mm (0.20 in)
Miniature male coaxial connector, 7.23 mm (0.285 in)maximum outside diameter “D”
8. Case length “B”, 30.48 mm (1.20 in)
9. 2.92 mm (0.115 in) maximum
10. Total length “C”, +30%, -0%
Figure 5: 3300 NSv Proximity Probes, Reverse Mount
Available Probes
330906, 3/8-24 UNF-2A
330907, M10x1 thread

Reverse mount probes are not available with armor orconnector protector options.

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990 Vibration Transmitter
Datasheet

141612 Rev. U

1. 7.2 mm (0.285 in) maximum diameter
2. Miniature male coaxial connector
3. FEP-coated or uncoated armor, armor length is 300 mm(11.8 in) less than cable length
4. 75Ω cable, 2.80 mm (0.11 in) maximum outside diameter,
7.6 mm (0.30 in) maximum outside diameter of armor, 7.0
mm (0.275 in) maximum outside diameter of uncoatedarmor
5. Stainless steel ferrules, 8.4 mm (0.33 in) diameter
6. FEP-insulated coaxial cable
7. Miniature female coaxial connector
8. Cable length +20%, -0%
Figure 6: 3300 NSv Extension Cable

1. To test adapter 122115-01

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990 Vibration Transmitter
Datasheet

141612 Rev. U

2. Receiver
3. Cable shield
4. Transmitter
5. Extension cable
6. Recommended wiring is shielded, twisted-pair, 1.0 mm (18AWG) (part number 02173006). Maximum length is 13 km(8 miles).
7. Power supply, VPS = 17 to 35 Vdc
8. Common (ground)
9. Probe
Figure 7: 990 Vibration Transmitter Loop Wiring Connections
The phase of the PROX OUT signal is inverted from the standard for Bently Nevada products.
Also, connecting grounded AC-powered equipment to PROX OUT may result in a false alarm.
Use test adapter 122115-01 to connect AC equipment to the transmitter. Note that the 122115-01
also inverts the PROX OUT signal.

1. Maximum loop resistance in ohms (RLOOP)
2. Power supply voltage (VPS)
3. Operating region
Figure 8: 990 Vibration Transmitter Maximum Loop ResistanceRLOOP = 43.5 x (Vps – 12) W maximum. If the maximum loop resistance is exceeded, then the
full-scale current does not reach 20 mA.

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990 Vibration Transmitter
Datasheet

141612 Rev. U

Copyright 2024 Baker Hughes Company. All rights reserved.

Bently Nevada and Orbit Logo are registered trademarks of Bently Nevada, a Baker Hughes business, in the UnitedStates and other countries. The Baker Hughes logo is a trademark of Baker Hughes Company. All other product andcompany names are trademarks of their respective holders. Use of the trademarks does not imply any affiliation
with or endorsement by the respective holders.
Baker Hughes provides this information on an “as is” basis for general information purposes. Baker Hughes does notmake any representation as to the accuracy or completeness of the information and makes no warranties of any
kind, specific, implied or oral, to the fullest extent permissible by law, including those of merchantability and fitness
for a particular purpose or use. Baker Hughes hereby disclaims any and all liability for any direct, indirect,
consequential or special damages, claims for lost profits, or third party claims arising from the use of theinformation, whether a claim is asserted in contract, tort, or otherwise. Baker Hughes reserves the right to makechanges in specifications and features shown herein, or discontinue the product described at any time without
notice or obligation. Contact your Baker Hughes representative for the most current information.
The information contained in this document is the property of Baker Hughes and its affiliates; and is subject tochange without prior notice. It is being supplied as a service to our customers and may not be altered or its content
repackaged without the express written consent of Baker Hughes. This product or associated products may becovered by one or more patents. See Bently.com/legal.

1631 Bently Parkway South, Minden, Nevada USA 89423
Phone: 1.775.782.3611 (US) or Bently.com/support
Bently.com

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