Bently Nevada 990 Specifications

990 Vibration Transmitter

Datasheet

Bently Nevada Machinery Condition Monitoring

Description

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).

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:

141612 Rev. P

l Integrated Proximitor Sensor requires no external unit

l Non-isolated “PROX OUT" and "COM" terminals plus a

coaxial connector to provide a dynamic vibration and
gap voltage signal output for diagnostics‡.

l Non-interacting zero and span potentiometers under

the Transmitter label supports loop adjustment.

l Test Input pin for quick verification of loop signal output,

using a function generator as the input.

l A Not OK/Signal Defeat circuit prevents high outputs or

false alarms due to a faulty proximity probe or loose
connection.

l Choice of DIN-rail clips or bulkhead mounting screws as

standard options simplifies mounting.

990 Vibration Transmitter
Datasheet 141612 Rev. P

l Potted construction for high humidity

(up to 100% condensing) environments.
Compatibility with 3300 NSv proximity
probe allows transducer installation in
small areas with minimal clearance,

conventions for signal polarity. We strongly
recommend the use of this test adapter for all
applications to maintain isolation between test
equipment and the loop signal, and ensure
that the installation maintains machinery
protection integrity.

typical of centrifugal air compressors.

Specifications

Channels configured for Velocity or
Acceleration can provide, Direct, 1X
amplitude/phase and 2X
amplitude/phase.

Notes

†

Vibration transmitters have many limitations
when compared to a continuous vibration
monitoring system. They are a practical
solution 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, the
4-20 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, an
interface is available (and strongly
recommended) for signal isolation. The 990/991
Test Adapter conditions the 990 Transmitter's
"PROX OUT" signal for use with ac-powered test
equipment. It also inverts and isolates the 990's
transducer signal, making it suitable for
equipment such as oscilloscopes and
analyzers, and preserving industry-standard

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

Power

4 to 20 mA
signal
output

4 to 20 mA
loop
accuracy

Probe gap

Maximum
loop
resistance

Current
limiting

Zero and
span

NOT
OK/signal
defeat

Power-up
inhibit

Accepts 1 non-contacting 3300 NSv
Proximity Probe and extension cable.

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

4 to 20 mAdc over specified full-scale
range in 2-wire configuration.

Within ±1.5% over specified full-scale
range. Accuracy is rated from the TEST
signal input to the voltage measured
across a 250 Ω 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.

23 mA typical.

Non-interacting external adjustments.

Signal 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.

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

2/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

Proximitor
sensor
output

Output
impedance

Prox out
linear range

Prox Out
incremental
scale factor

Temperature
stability

Frequency
response

Minimum
target size

Leadwire
length

Non­Hazardous,
Zone 2 or Div
2 Hazardous
area
locations

Intrinsically
Safe
Hazardous
area
locations

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

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

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

7.87 mV/µm (200 mV/mil) ± 6.5%
typical including interchangeability
errors when measured 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.

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

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

9.5 mm (0.375 in) diameter.

Maximum for Proximitor Sensor
Output (BNC connector), maximum
cable distance is 3 metres (10 feet).

Power Supply: 28V

Zone 0/1

Terminal
Terminal
blocks E1­E2 “power
supply 4­20 mA”

Ui [28 V Uo[28 V Uo[ 28 V

Ii [120 mA Io [6 mA

Pi[ 0.84 W

Ci [20 nF Co [ 80 nF

Li [10 μH Lo [1H Lo [5.3 mH

blocks E3-

E4 and

connector

J2

"Proximitor"

Po [ 0.17

W

Connector
J3 "Probe"

Io [ 100
mA

Po [ 0.8 W

Co[ 27.3
nF

General Purpose Approval by

Electrical
classification

Canadian Standards Association
(CSA/NRTL/C) in North America and
by VDE in Europe. 990 has the CE
mark for Europe

Maritime Approvals

American Bureau of
Shipping (ABS) Type
Approval

Certification Number: 06­HS177078-3-PDA

Environmental Limits

Transmitter Temperature

Operating
temperature

Storage
temperature

Probe Temperature

Operating
temperature

Storage
temperature

Relative
humidity

-35 °C to +85 °C (-31 °F to +185 °F)

-51 °C to +100 °C (-60 °F to +212 °F).

-35 °C to +177 °C (-31 °F to +350 °F).

-51 °C to +177 °C (-60 °F to +350 °F).

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

Mechanical

Transducer
tip material

Transducer
case material

Probe Cable

Cable armor
(optional)

Tensile
strength

Transmitter
weight

Total system
weight

Polyphenylene sulfide (PPS).

AISI 303 or 304 Stainless Steel (SST).

75Ω coaxial, fluoroethylene
propylene (FEP) insulated.

Flexible AISI 302 SST with optional FEP
outer jacket.

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

0.43 kg (0.9 lbm).

0.82 kg (1.8 lbm) typical.

3/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

Compliance and Certifications

FCC

This device complies with part 15 of the
FCC Rules. Operation is subject to the
following two conditions:

l This device may not cause harmful

interference.

l This device must accept any

interference received, including
interference 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



4/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

Hazardous Area Approvals

For the detailed listing of country and product
specific approvals, refer to the Approvals Quick
Reference Guide (108M1756) available from

Bently.com.

CSA/NRTL/C

Class I, Div 2
Groups A, B, C, D

T5@ Ta [+85°C, Type 4

Installed per Drawing 128838

ATEX/IECEx

II 1 G

Ex ia IIC T4 Ga

T4 @ Ta = -35°C to +85°C

II 3 G

Ex nA IIC T4 Gc
T4 @ Ta= -35 ˚C to + 85˚C



Entity Parameters

Zone 2

Power Supply: 28V

Zone 0/1

Terminal blocks
E1-E2 “power
supply 4-20
mA”

Ui [28 V Uo[28 V Uo[ 28 V
Ii [120 mA Io [6 mA Io [ 100 mA
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 [1H Lo [5.3 mH

Terminal blocks
E3-E4 and
connector J2
"Proximitor"

Connector J3
"Probe"

5/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

Minimum length: 0 in

Ordering Information

For the detailed listing of country and product
specific approvals, refer to the Approvals Quick
Reference Guide (108M1756) available from

Bently.com.

990-AA-BB-CC-DD

A: Full-scale Option
0 4 0-4 mils pp (0-100 μm pp)
0 5 0-5 mils pp (0-125 μm pp)
B: System Length Option
5 0 5.0 metres (16.4 feet)
7 0 7.0 metres (23.0 feet)
C: Mounting Option
0 1 35 mm DIN rail clips
0 2 Bulkhead screws
0 3 DIN clips and screws
D:Agency Approval Option
0 0 Not required
0 1 CSA Division 2

CSA Division 2, ATEX Zone 0, ATEX

0 5

3300 NSv Proximity Probes,
Standard

Zone 2 and includes ABS maritime
approval

Maximum length: 9.2 in
Example: 0 4 0.4 in

B: Case Length Option

Order in increments of 0.1 in
Minimum length: 0.8 in
Maximum length: 9.9 in
Example: 3 5 3.5 in

C:  Total Length Option
0 5 0.5 metre (1.67 feet)
1 0 1.0 metre (3.25 feet)
5 0 5.0 metres (16.4 feet)
7 0 7.0 metres (23 feet)
D:  Connector Option

Miniature coaxial ClickLoc connector

0 1

0 2

1 1

1 2

E: Agency Approval Option
0 0 Not required

0 5

with connector protector, standard
cable

Miniature coaxial ClickLoc connector,
standard cable

Miniature coaxial ClickLoc connector
with connector protector, FluidLoc
cable

Miniature coaxial ClickLoc connector,
FluidLoc cable

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

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

330901

330902

330908

330909

A:Unthreaded Length Option

Unthreaded length must be at least 0.7 in. less

than the case length.
Order in increments of 0.1 in

Length configurations

3300 NSv Probe, 1/4-28 UNF thread,
without armor.

3300 NSv Probe, 1/4-28 UNF thread,
with armor.

3300 NSv Probe, 3/8-24 UNF thread,
without armor.

3300 NSv Probe, 3/8-24 UNF thread,
with armor.

3300 NSv Probes, Metric

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

330903

330904

330905

330910

A: Unthreaded Length Option

Unthreaded length must be at least 20 mm less

than the case length.
Order in increments of 10 mm

6/15

3300 NSv Probe, M8 x 1 thread,
without armor.

3300 NSv Probe, M8 x 1 thread, with
armor.

3300 NSv Probe, M10 x 1 thread,
without armor.

3300 NSv Probe, M10 x 1 thread, with
armor.

990 Vibration Transmitter
Datasheet 141612 Rev. P

Minimum length: 0 mm
Maximum length: 230 mm
Example 0 6 60 mm

B: Case Length Option

Order in increments of 10 mm
Minimum length: 20 mm
Maximum length: 250 mm
Example: 25 = 250 mm

C: Total Length Option
0 5 0.5 metre (1.67 feet)
1 0 1.0 metre (3.25 feet)
5 0 5.0 metres (16.4 feet)
7 0 7.0 metres (23 feet)
D:  Connector Option

Miniature coaxial ClickLoc connector

0 1

0 2

1 1

1 2

E: Agency Approval Option
0 0 Not required

0 5

with connector protector, standard
cable

Miniature coaxial ClickLoc connector,
standard cable

Miniature coaxial ClickLoc connector
with connector protector, FluidLoc
cable

Miniature coaxial ClickLoc connector
attached, FluidLoc cable

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

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
0 5 0.5 metre (1.67 feet)
1 0 1.0 metre (3.25 feet)
5 0 5.0 metres (16.4 feet)
7 0 7.0 metres (23 feet)
D: Connector Option

0 2

12

E: Agency Approval Option
0 0 Not required

0 5

Miniature coaxial ClickLoc connector,
standard cable

Miniature coaxial ClickLoc connector
attached, FluidLoc cable

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

Extension Cable

330930-AAA-BB-CC

A: Cable Length Option
0 4 0 4.0 metres (13.1 feet)
0 4 5 4.5 metres (14.8 feet)
0 6 0 6.0 metres (19.7 feet)
0 6 5 6.5 metres (21.3 feet)
B Armor Option
0 0 Without stainless steel armor

0 1

0 2 With stainless steel armor

0 3

0 4

0 5

C: Agency Approval Option

With FEP covered stainless steel
armor

Without stainless steel armor, with
connector protector

With FEP covered stainless steel
armor and connector protector

With stainless steel armor and
connector protector

7/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

0 0 Not Required

Multiple Approvals (CSA NRTL/C and

0 5

BASEEFA/CENELEC (which includes
CSA Division 2)



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 Transmitter so that you can
connect 990 Transmitters to AC­powered diagnostic equipment. The
Adapter modifies the PROX OUT
signal so that it matches our
standard Proximitor sensor signals
by performing these functions:

l Shifts the phase of the PROX

OUT signal by 180º by
changing the voltage from
positive to negative

l Shifts the phase of the PROX

OUT signal by 180º by

122115-01

changing the voltage from
positive to negative

l Shifts the phase of the PROX

OUT signal by 180º by
changing the voltage from
positive to negative

The 990/991 Test Adapter
provides the following benefits:

l Small size and weight for

portable operation

l Battery or AC adapter power

options

l Automatic shutoff circuit that

powers down the unit when
the battery is low

l 2 channels, so that you can

display an orbit for XY probe
configurations.

990/991 Test Adapter Accessories

123266-01Coaxial Cable Kit. Includes 4 cables with

length of 1.5 metres (5 feet) each.

02211505

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

990/991 Test Adapter Spare Parts

01810700 Battery (9 volt alkaline).

AC adapter. Has universal AC input to 9

02270056

02198937

123133 990 Test Adapter User Guide

volts DC output. Input is 108 to 132 Vac
with 120 Vac nominal, or 207 to 253 Vac
with 240 Vac nominal.

Power cord (for North American AC
power outlet).

Probe and Transmitter Accessories

Bulk cable (specify length in feet). 1.0
mm2 (18 AWG), 2-conductor, twisted,

02173006

123655

330153­05

163356

330951-01990 Mounting Screws (spares). Contains

284726



shielded cable used for the 4 to 20 mA
loop. Also used for the PROX OUT signal
on the 990 Transmitter's terminal strip.

990/991 Transmitter System Installation
User Guide

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

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

4 screws.
DIN rail mounting kit. Installed on the 990

Transmitter to allow mounting on 35 mm
DIN rail.



8/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

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)

9/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

1. Probe tip, 5.26 mm (0.207 in) maximum diameter

2. Hexagonal nut

Figure 3: 3300 NSv Proximity Probes, Standard Mount



Available Probes

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

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%

Standard mounts Supplied with these wrench flats

1/4-28 UNF thread probes 7/16-inch lock nut and 7/32 inch
M8x1 thread probes 13-mm lock nut and 7 mm.
3/8-28 UNF thread probes 9/16-inch lock nut and 5/16-inch.
M10x1 thread probes 17-mm lock nut and 8 mm.



10/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

1. 12 mm (0.49 in) maximum diameter
2. 36.3 mm (1.43 in) maximum
3. 51.1 mm (2.01 in) maximum
4. Connector protector (fluorosilicone material)

Figure 4: Installed Connector Protectors

Available Probes

1. Probe tip, 5.26 mm (0.207 in) maximum diameter
2. Hexagonal nut
3. Case thread
4. 75Ω cable, 2.8 mm (0.11 in) outside diameter
5. 5.08 mm (0.20 in)
6. Unthreaded case length “A”, 5.08 mm (0.20 in)

7. 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

Reverse mount probes are not available with armor or connector

11/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

330906, 3/8-24 UNF-2A
330907, M10x1 thread




protector options.



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 uncoated

armor
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

12/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

1. To test adapter 122115-01
2. Receiver
3. Cable shield
4. Transmitter
5. Extension cable
6. Recommended wiring is shielded, twisted-pair, 1.0 mm (18

AWG) (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.

13/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

1. Maximum loop resistance in ohms (R

LOOP

)

2. Power supply voltage (VPS)

3. Operating region

Figure 8: 990 Vibration Transmitter Maximum Loop Resistance

RLOOP = 43.5 x (Vps – 12) W maximum. If the maximum loop resistance is exceeded, then the full­scale current will not reach 20 mA.

14/15

990 Vibration Transmitter
Datasheet 141612 Rev. P

Copyright 2020 Baker Hughes Company. All rights reserved.

Bently Nevada, Orbit Logo, System 1 and Proximitor are registered trademarks of Bently Nevada, a Baker Hughes
Business, in the United States and other countries. The Baker Hughes logo is a trademark of Baker Hughes
Company. All other product and company 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
not make 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 the
information, whether a claim is asserted in contract, tort, or otherwise. Baker Hughes reserves the right to make
changes 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 to
change 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 be
covered by one or more patents. See Bently.com/legal.



1631 Bently Parkway South, Minden, Nevada USA 89423

Phone: [phone] or 1.800.227.5514 (US only)

Bently.com

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