3500/46M Hydro Monitor
Datasheet

Bently Nevada Machinery Condition Monitoring

144408 Rev. AB

Description
The 3500/46M Hydro Monitor is a four-channel instrumentthat accepts input from proximity, seismic, dynamic pressure
and air gap sensors. The monitor conditions the signal toprovide vibration, position and both static and dynamic
pressure measurements. It then compares the conditioned
signals with user-programmable alarms. Hydro Radial
Vibration channels combine the shaft gap movement with
the NX amplitude to provide a measurement to alarm on
shear-pin failure.
Using the 3500 Rack Configuration Software, you canconfigure the 3500/46M Hydro Monitor to perform thefollowing functions:
l
l
l
l
l
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l
l
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l
l
l

Hydro Radial Vibration
Hydro Air Gap
Hydro Velocity
Hydro Acceleration
Hydro Thrust
Multimode Hydro RV
Multimode Air Gap
Multimode Hydro Velocity
Multimode Thrust
Multimode Acceleration
Multimode Hydro Dynamic Pressure
Hydro Stator End Winding (SEW)The monitor channels are programmed in pairs.
Each channel may have separate or identicalconfigurations.

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

The primary purpose of the 3500/46M Hydro
Monitor is to provide the following:llMachinery protection by continuously
comparing monitored parametersagainst configured alarm setpoints todrive alarms
Essential machine information for
operations and maintenance personnel
Hydro Velocity channels provide early
warning of pending machinery
problems and assist in diagnosing
them. Due to the nature of highamplitude, low frequency velocity
events, the Hydro Velocity channel
type cannot be used for automatedmachinery protection.

Each channel, depending on configuration,
typically conditions its input signal to generatevarious parameters called static values. You
can configure alert setpoints for each active
static value and danger setpoints for any twoof the active static values.
You can configure multimode channels to haveup to eight sets of alarm parameters including
alert and danger set points and alarm timedelays. Each set may be configured for a
specific machine mode.
As the machine changes modes, the monitor
can switch to a specific set using contacts on
multimode I/O modules or softwarecommands through a communications
gateway.

2/16

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

Specifications
InputsSignal

Accepts 1 to 4 proximity, airgap, velocity or acceleration
sensor signalsPowerconsumption

7.7 watts, typicalMultimode
positive input
I/O

10.19 mV/m/s2 (100 mV/g)

Multimode
Hydro
Dynamic
Pressure

Refer to the Bently Nevada
350300 Dynamic Pressure
Sensor datasheet, document
110M4613

Outputs
Front Panel LEDs
OK LED

Indicates when the 3500/46M
Hydro Monitoris operating
properly

TX/RX LED

Indicates when the 3500/46M
Hydro Monitor iscommunicating with othermodules in the 3500 Rack.

Bypass LED

Indicates when the 3500/46M
Hydro Monitor is in Bypass
Mode.

50 kΩ

Input ImpedanceProx/Velom
I/O andMultimode
Prox/Velom
I/O

Hydro SEW

10 kΩ for Prox/Accel
3.5 MΩ for Velomitor

Sensitivity
Hydro Radial
Vibration andMultimode
Hydro RV

0.79 mV/μm (20 mV/mil),
3.94 mV/μm (100 mV/mil) or
7.87 mV/μm (200 mV/mil)Hydro Air Gap
andMultimode Air
Gap

0.20 mV/μm (5 mV/mil),
0.22 mV/μm (5.6 mV/mil),
0.49 mV/μm (12.5 mV/mil) or
0.55 mV/μm (14 mV/mil)

Hydro
Velocity andMultimode
Hydro
Velocity

20 mV/mm/s (508 mV/in/s)

Hydro ThrustandMultimode
Thrust3.94 mV/μm (100 mV/mil),
7.87 mV/μm (200 mV/mil) or
11.22 mV/μm (285 mV/mil)Hydro
Acceleration
andMultimode
Acceleration

1.02 mV/m/s2 (10 mV/g) or
2.55 mV/m/s2 (25 mV/g)

BufferedTransducer
Outputs
OutputImpedance

The front of each monitor has
one coaxial connector foreach channel.
Each connector is short-circuit
protected.
550 ΩTransducer Power Supply

3/16

Prox/Velom
I/O andMultimode
Prox/Velom
I/O-23 Vdc nominal at 43 mA
max

Multimode
Positive Input
I/O+23 Vdc nominal at 23 mA
max

3500/46M Hydro Monitor
Datasheet

Recorder144408 Rev. AB+4 to +20 mA. Output is
proportional to monitor fullscale.

Constant Q Filter
Minimum rejection in
stopband of –50 dB

One output is provided foreach channel.

The N value in NX is selectablebetween 2 and 20 (formachine speeds of 25 cpm to
1,500cpm) or 2 to 50 (formachine speeds of 25 cpm to
600 cpm).
1X and NX vector, Not 1X andcomposite parameters arevalid for machine speeds per
selected NX value range.

1X and NX
vector filter

Monitor operation isunaffected by short circuits onrecorder outputs.
VoltageCompliance(current
output)Resolution

0 to +12 Vdc range across load
Load resistance is 0 to 600 Ω.
0.3662 µA per bit±0.25% error at room
temperature

Composite±0.7% error over temperature
range

Accuracy

Update rate 100 ms or lessDirect andGap

Within ±0.33% of full-scale
typical±1% maximum

1X and NX

Within ±0.33% of full-scale
typical±1% 1X maximum±3% NX maximumNot 1X±1% of full-scale typical±3% maximum

Composite±1% of full-scale typicalSignal Conditioning
Specified at +25 ºC (+77 ºF) unlessotherwise noted.

Hydro and Multimode Hydro Radial
Vibration
Frequency Response
Direct filter

Hydro Air Gap and Multimode Air Gap

0.104 Hz to 500 Hz
Rotor speed is 25 to 1,500 cpm.

Gap filter-3 dB at 0.05 Hz

Not 1X filter

0.25 to 128 times rotor speed
Constant Q notch filter
Minimum rejection in
stopband of -50 dB

NX amplitude multiplied by thepercent change in gap from its
zero position
Specific for detecting Shear Pin
failure

4/16

Instantaneous
Air Gap

Provides instantaneous gap
measurements when thepole-passing rate slows toless than one pole/second

Average Air
Gap

The monitor measures eachpole gap and averages thevalues for all poles together
over one revolution.

Minimum Air
Gap

The minimum pole gap
value in a revolution

3500/46M Hydro Monitor
Datasheet

Maximum Air
Gap

The maximum pole gap
value in a revolution

Min Air Gap
Pole Number

The pole number detectedwith the minimum gap
value in a revolution

144408 Rev. AB

Constant Q Filter
Minimum rejection in
stopband of –51 dB
1X and 2X
vector filter

The pole number detectedwith the maximum gap
value in a revolution
Max Air Gap
Pole Number

Filter Quality

All values except
instantaneous Air Gap are
valid when the polespassing rate is between 1
and 200 poles/second.

Accuracy
Average Air
Gap

Within ±0.33% of full scale
typical±1% maximum

Minimum Air
Gap

Within ±0.33% of full scale
typical±1% maximum

Maximum Air
Gap

Within ±0.33% of full scale
typical±1% maximum

Low Mode: Valid for machine
speeds of 60 to 6,000 cpm
High Mode: Valid formachine speeds of 60 to
24,600 cpm

High-pass

4-pole (80 dB per decade,24 dB per octave)

Low-pass

2-pole (40 dB per decade,
12dB per octave)

Accuracy

DirectWithin ±1% of full-scale
typical±2% maximum
Exclusive of filters

1X Amplitude

Within ±1% of full-scale
typical±2% maximum
Exclusive of filters

Hydro Velocity and Multimode Hydro
Velocity

2X Amplitude

Within ±1% of full-scale
typical±2% maximum
Exclusive of filters

Frequency Response

Hydro Thrust and Multimode Thrust

Low-pass filter
Bias

DirectFrequency Response

Low Mode: -3dB at 0.02 Hz
High Mode: -3dB at 0.07 Hz
Low Mode: 0.1875 to 343.75
Hz, -3dB
High Mode: 0. 75 to 1375 Hz, 3dB

Direct filter-3dB at 1.2 Hz

Gap filter-3dB at 0.4 1 Hz

Accuracy
Direct

5/16

Within ±0.33% of full-scale
typical±1% maximum

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

Hydro Acceleration and Multimode
Acceleration
Frequency Response
Bias filter

Low-pass filter-3dB at 0.01 Hz

Not OK filter

Low-pass filter-3dB at 2400 Hz

1X and 2X
vector filter

Constant Q Filter
Minimum rejection in
stopband of –51 dB
Valid for machine speeds of
60 cpm to 60,000 cpm
See Frequency Ranges Multimode Acceleration
Channel on the next page.

Pole Pass
Amplitude

2x line frequency (100 Hz or
120 Hz)Constant Q filter (Q=20)
Minimum rejection in stopband of -60 dB

DirectResultant

5.0 Hz to 800 Hz (-3dB
corners)
Resultant of both X and Y
axis inputs

Pole Pass
Resultant

2x line frequency (100 Hz or
120 Hz)Constant Q filter (Q=20)
Minimum rejection in stopband of -60 dB
Resultant of both X and Y
axis inputs

Accuracy

Filter Quality

Direct±1% of Full Scale maximum

Bias voltage±1% of Full Scale maximum

Pole Pass
Amplitude±2% of full-scale typical±3% maximum

DirectResultant±1% of full-scale typical±2% maximum

Pole Pass
Resultant±2% of full-scale typical±3% maximum

High pass

4-pole (80 dB per decade,24dB per octave)

Low pass

4-pole (80 dB per decade,24dB per octave)

DirectWithin ±0.33% of full scale
typical±1% maximum
Exclusive of filters

1X Amplitude

Within ±0.33% of full scale
typical±1% maximum
Exclusive of filters

Multimode Hydro Dynamic Pressure

Within ±0.33% of full scale
typical±1% maximum
Exclusive of filters

Low mode

0.1875 Hz to 343.7500 Hz

High mode

0.75 Hz to 1375.00 Hz

2X Amplitude

Frequency Response

Filter Quality

Hydro Stator End Winding (SEW)High pass

4-pole(80 dB per decade,24 dB per octave)

Low pass

4-pole(80 dB per decade,24 dB per octave)

Frequency Response
Direct5.0 Hz to 800 Hz (-3dB
corners)

Bias voltage

DC to 0.05 Hz (-3dB)

6/16

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

Alarms

Accuracy
Peak Direct
amplitud±1% of Full Scale
maximum

RMS Direct
amplitude±2% of Full Scale
maximum

Static Pressure±0.87% of Full Scale
maximumAlarm
setpoints

Frequency Ranges - Multimode
Acceleration Channel
The following table lists the frequency ranges
for the monitor under different options using
the Multimode Acceleration Channel type:Output Type

Non-Integrated(Hz)

Integrated
(Hz)

RMS

10 to 30,000

10 to 20,000

Peak

3 to 30,000

3 to 20,000

Physical
241.3 mm x 24.4 mm x241.8 mm
(9.50 in x 0.96 in x 9.52 in)Weight0.91 kg (2.0 lb)

I/O Modules
Dimensions(Height x Width x
Depth)

241.3 mm x 24.4 mm x 99.1
mm
(9.50 in x 0.96 in x 3.90 in)

Weight0.20 kg (0.44 lb)

Within 0.13% of the desired
value

Hydro Radial
Vibration

DirectGap
Not 1X Amplitude
1X Amplitude
NX Amplitude
Composite
1X Phase Lag
NX Phase Lag

Multimode
Hydro RV

DirectGap
Not 1X Amplitude
1X Amplitude
NX Amplitude
Composite
1X Phase Lag

Hydro Air Gap
Average Air Gap
and Multimode
Minimum Air Gap
Air Gap
DirectHydro Velocity 1X Amplitudeand Multimode 2X Amplitude
Hydro Velocity 1X Phase Lag
2X Phase Lag

Rack Space Requirements
Monitor
Module1 full-height front slot

I/O Modules

1 full-height rear slot

Alarms are adjustable from0 to 100% of full-scale foreach measured value
except when the full-scale
range exceeds the range ofthe transducer. In this case,the range of the transducer
will limit the setpoint.

Alarm
accuracy

Monitor Module (Main Board)
Dimensions(Height x Width x
Depth)

Use Rack Configuration
Software to set alert levels
for each value measured by
the monitor and danger
setpoints for any two of thevalues measured by themonitor.

Hydro Thrust
Directand Multimode
Gap
Thrust7/16

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

DirectHydro
1X Amplitude
Acceleration
2X Amplitudeand Multimode
1X Phase Lag
Acceleration
2X Phase Lag
Hydro Stator
End Winding(SEW)

DirectPole Pass Amplitude
Direct Resultant
Pole Pass Resultant

DirectStatic Pressure
Multimode
1X Amplitude
Hydro Dynamic
2X Amplitude
Pressure
1X Phase Lag
2X Phase Lag

Alarm Time Delays
You can program alarm delays using
Rack Configuration Software.

Alert

From 1 to 400 seconds in one
second intervals

DangerFrom 1 to 400 seconds in one
second intervals

Multimodechannels

You can set delays for eachmeasured value that has
alarm set points.

Standard
channels

You can set one alert anddanger delay for thechannel.

8/16

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

3500/46M Hydro Monitor Measured
Variables
Measured variables are used to monitor themachine. The 3500/46M provides the following
measured variables:

Hydro Radial
Vibration

Multimode
Hydro RV

Hydro Air Gap

DirectGap
1X Amplitude
1X Phase Lag
NX Amplitude
NX Phase Lag
Not 1X Amplitude
Composite Amplitude
DirectGap
1X Amplitude
1X Phase Lag
NX Amplitude
Not 1X Amplitude
Composite Amplitude
Mode
Average Air Gap
Instantaneous Air Gap
Minimum Air Gap
Maximum Air Gap
Minimum Air Gap Pole
NumberMaximum Air Gap Pole
NumberMultimode Air
Gap

Average Air Gap
Instantaneous Air Gap
Minimum Air Gap
Maximum Air Gap
Minimum Air Gap Pole
NumberMaximum Air Gap Pole
NumberMode

Hydro Velocity

DirectBias
1X Amplitude
1X Phase Lag
2X Amplitude
2X Phase Lag

Multimode
Hydro Velocity

DirectBias
1X Amplitude
1X Phase Lag
2X Amplitude
2X Phase Lag
ModeHydro Thrust

DirectGap

Multimode
ThrustDirect
Gap
Mode

Hydro
Acceleration

DirectBias
1X Amplitude
1X Phase Lag
2X Amplitude
2X Phase Lag

Multimode
Acceleration

DirectBias
1X Amplitude
1X Phase Lag
2X Amplitude
2X Phase Lag
ModeHydro Stator
End Winding(SEW)

DirectBias Voltage
Pole Pass Amplitude
Direct Resultant
Pole Pass Resultant

DirectStatic Pressure
Multimode
1X Amplitude
Hydro Dynamic 1X Phase Lag
Pressure
2X Amplitude
2X Phase Lag
Mode

9/16

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

Hazardous Area Approvals

Compliance and Certifications
FCC

For the detailed listing of country andproduct-specific approvals, refer tothe Approvals Quick Reference Guide(108M1756).

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

For additional technicaldocumentation, please log in to
bntechsupport.com and access the
Bently Nevada Media Library.

This device may not cause harmfulinterference.
This device must accept any
interference received, includinginterference that may cause
undesired operation.

cNRTLus

EMC

Class I, Zone 2: AEx/Ex nA nC ic IIC T4 Gc;
Class I, Zone 2: AEx/Ex ec nC ic IIC T4 Gc;
Class I, Division 2, Groups A, B, C, and D;

European Community Directive:
EMC Directive 2014/30/EU

T4 @ Ta= -20˚C to +65˚C (-4˚F to +149˚F)
When installed per drawing 149243 or
149244.

Standards:
EN 61000-6-2; Immunity for
Industrial Environments
EN 61000-6-4; Emissions for
Industrial Environments

ATEX/IECEx
II 3 GElectrical Safety

Ex nA nC ic IIC T4 Gc
Ex ec nC ic IIC T4 Gc

European Community Directive:

T4 @ Ta= -20˚C to +65˚C(-4˚F to +149˚F)
When installed per drawing 149243 or
149244.

LV Directive 2014/35/EU
Standards:
EN 61010-1

RoHS
European Community Directive:
RoHS Directive 2011/65/EU

Maritime
DNV GL rules for classification – Ships,
offshore units, and high speed and lightcraft
ABS Rules for Condition of Classification,
Part 1ll

Steel Vessels Rules
Offshore Units and Structures

10/16

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

Ordering Considerations
The 3500/46M Hydro Monitor requires the following or later revisions of these firmware and software
products:
3500/46M
FirmwareVersionApplication

3500/01
SoftwareVersion3500/02
SoftwareVersion3500/03
SoftwareVersionHydro Radial Vibration

2.02

2.70

2.21

1.22

Hydro Air Gap

2.09

3.40

2.30

1.30

Hydro Velocity

2.10

3.70

2.50

1.50

Hydro Acceleration

2.40

4.40

Hydro Thrust

2.40

4.40

Multimode Hydro RV

2.40

3.80

2.51

1.51

Multimode Air Gap

2.40

3.80

2.51

1.51

Multimode Hydro Velocity

2.40

3.80

2.51

1.51

Multimode Thrust

2.40

3.80

2.51

1.51

Multimode Acceleration

2.40

3.80

2.51

1.51

Hydro Stator End Winding (SEW)

4.10

3.93

2.52

1.52

Multimode Hydro Dynamic Pressure

4.21

5.20

3500/46M
Hardware3500/22
Firmware3500/92
System 1
FirmwareMultimode applications
using software commands to change monitor
modes

1.32

1.16

Multimode applications
incorporating the 3500/94 display

1.60

2.30

Applications requiring full multimode support
from System 1 software

1.32

Application
Multimode applications
using hardware contacts to change monitor
modes

Revision S MultimodeI/O Modules

11/16

6.0

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

Other Requirements and Restrictions
A multimode recorder ET block must be used with an external termination multimode I/O module. To
connect these components, you must use a signal cable, part number 129525. The ET block provides
recorder outputs and mode inputs.
External Termination Blocks cannot be used with Internal Termination I/O Modules.
When ordering I/O modules with External Terminations, the External Termination Blocks and cables
must be ordered separately.

12/16

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

Ordering Information
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.

Hydro Monitor
3500/46 - AA-BB
A: I/O Module Type01

Prox/Velom I/O Module with Internal
Terminations

02

Prox/Velom I/O Module with External
Terminations

03

Multimode Prox/Velom I/O Modulewith Internal Terminations

04

Multimode Prox/Velom I/O Modulewith External Terminations

05

Multimode Positive Input I/O Modulewith Internal Terminations

06

Multimode Positive Input I/O Modulewith External Terminations

None

01

cNRTLus (Class 1, Division 2)

02

ATEX/IECEx/CSA (Class 1, Zone 2)

125808-12

Multimode Positive Input
External Termination BlockEuro Style connectors

125808-13

Multimode Recorder Output
and Mode Input External
Termination BlockEuro Style connectors

128702-01

Recorder External
Termination BlockEuro Style connectors

128015-08

Prox/Velom External
Termination Block
Terminal Strip Connectors

128015-11

Multimode Prox/Velom
External Termination Block
Terminal Strip connectors

128015-12

Multimode Positive Input
External Termination Block
Terminal Strip connectors

128015-13

Multimode Recorder Output
and Mode Input External
Termination Block
Terminal Strip connectors

128710-01

Recorder External ET Block
Terminal Strip connectors

3500 Transducer (XDCR) to External
Termination (ET) Block Cable
129525 - AAAA-BB
A: I/O Cable Length

External Termination Blocks
125808-08

Multimode Prox/Velom
External Termination BlockEuro Style connectors

Cables

B: Hazardous Area Approval Option
00

125808-11

Prox/Velom External
Termination BlockEuro Style connectors

13/16

0005

5 feet (1.5 metres)

0007

7 feet (2.1 metres)0010

10 feet (3.0 metres)

0025

25 feet (7.6 metres)3500/46M Hydro Monitor
Datasheet0050

50 feet (15.2 metres)

0100

100 feet (30.5 metres)

144408 Rev. AB

169459-02

Multimode Prox/Velom I/O
Module with External
Terminations

169715-01

Multimode Positive Input I/OModule with Internal
Terminations

169715-02

Multimode Positive Input I/OModule with External
Terminations

00561941

Prox/Velom and Multimode
Prox/Velom I/O Module ten-pin
connector shunt

00580434

Euro Style connector header
8 pin
For use on I/O modules withinternal terminations

00580432

Euro Style connector header
10 pinFor use on I/O modules withinternal terminations

166M2389

Connector header
Push-in-spring type
(Alternative for PN 00580434)

166M2388

Connector header
Push-in-spring type
(Alternative for PN 00580432)

B: Assembly Instructions
01

Not Assembled

02

Assembled

3500 Recorder Output to External
Termination (ET) Block Cable (NonMultimode)
129529 - AAAA-BB
A: I/O Cable Length0005

5 feet (1.5 metres)

0007

7 feet (2.1 metres)0010

10 feet (3.0 metres)

0025

25 feet (7.6 metres)0050

50 feet (15.2 metres)

0100

100 feet (30.5 metres)

B: Assembly Instructions
01

Not Assembled

02

Assembled

Spares176449-06

3500/46M Hydro Monitor

144403-01

3500/46M Hydro Monitor User
Guide

140471-01

Prox/Velom I/O Module with
Internal Terminations

140482-01

Prox/Velom I/O Module with
External Terminations

169459-01

Multimode Prox/Velom I/O
Module with Internal
Terminations

14/16

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

Graphs and Figures

1.
2.
3.
4.
5.

Status LEDs
Buffered Transducer Outputs
Prox/Velom I/O Module with Internal Terminations
Prox/Velom I/O Module with External Terminations
Multimode Prox/Velom I/O Module with Internal
Terminations
6. Multimode Prox/Velom I/O Module with External
Terminations
7. Multimode Positive Input I/O Module with Internal
Terminations
8. Multimode Positive Input I/O Module with External
Terminations
Figure 1: Front and Rear Views of the 3500/46M Hydro Monitor

15/16

3500/46M Hydro Monitor
Datasheet

144408 Rev. AB

Copyright 2024 Baker Hughes Company. All rights reserved.

Bently Nevada, M2, System 1, Velomitor and Orbit Logo 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 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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