Bently Nevada 3500/46M Data sheet

3500/46M Hydro Monitor

Datasheet

Bently Nevada Machinery Condition Monitoring

Description

The 3500/46M Hydro Monitor is a four-channel instrument
that accepts input from proximity, seismic, dynamic pressure
and air gap sensors. The monitor conditions the signal to
provide 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 can
configure the 3500/46M Hydro Monitor to perform the
following functions:

l Hydro Radial Vibration
l Hydro Air Gap
l Hydro Velocity
l Hydro Acceleration
l Hydro Thrust
l Multimode Hydro RV
l Multimode Air Gap
l Multimode Hydro Velocity
l Multimode Thrust
l Multimode Acceleration
l Multimode Hydro Dynamic Pressure
l Hydro Stator End Winding (SEW)

144408 Rev. Y

The monitor channels are programmed in pairs. Each
channel may have separate or identical
configurations.



3500/46M Hydro Monitor
Datasheet 144408 Rev. Y



The primary purpose of the 3500/46M Hydro
Monitor is to provide the following:

l Machinery protection by continuously

comparing monitored parameters
against configured alarm setpoints to
drive alarms

l 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 high
amplitude, low frequency velocity
events, the Hydro Velocity channel type
cannot be used for automated
machinery protection.

Each channel, depending on configuration,
typically conditions its input signal to generate
various parameters called static values. You
can configure alert setpoints for each active
static value and danger setpoints for any two
of the active static values.

You can configure multimode channels to
have up to eight sets of alarm parameters
including alert and danger set points and
alarm time delays. 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 software
commands through a communications
gateway.

2/16

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y

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

Specifications

Inputs

Signal

Accepts 1 to 4 proximity, air
gap, velocity or acceleration
sensor signals

Multimode
Hydro
Dynamic
Pressure

Outputs

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

Power
consumption

Multimode
positive input
I/O

Input Impedance

Prox/Velom
I/O and
Multimode
Prox/Velom
I/O

Sensitivity

Hydro Radial
Vibration
and
Multimode
Hydro RV

Hydro Air
Gap and
Multimode
Air Gap

Hydro
Velocity and
Multimode
Hydro
Velocity

Hydro
Thrust and
Multimode
Thrust

Hydro
Acceleration
and
Multimode
Acceleration

0.79 mV/μm (20 mV/mil),

3.94 mV/μm (100 mV/mil) or

7.87 mV/μm (200 mV/mil)

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)

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

3.94 mV/μm (100 mV/mil),

7.87 mV/μm (200 mV/mil) or

11.22 mV/μm (285 mV/mil)

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

2.55 mV/m/s2 (25 mV/g)

7.7 watts, typical

50 kΩ

10 kΩ for Prox/Accel

3.5 MΩ for Velomitor

Front Panel LEDs

OK LED Indicates when the 3500/46M Hydro

Monitoris operating properly

TX/RX
LED

Bypass
LED



Buffered
Transducer
Outputs

Output
Impedance

Transducer Power Supply

Prox/Velom
I/O and
Multimode
Prox/Velom
I/O

Multimode
Positive
Input I/O



Recorder

Indicates when the 3500/46M Hydro
Monitor is communicating with
other modules in the 3500 Rack.

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

The front of each monitor has
one coaxial connector for each
channel.

Each connector is short-circuit
protected.

550 Ω

-23 Vdc nominal at 43 mA max

+23 Vdc nominal at 23 mA max

+4 to +20 mA. Output is
proportional to monitor full­scale.

One output is provided for each
channel.

3/16

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y

Monitor operation is unaffected
by short circuits on recorder
outputs.

Voltage
Compliance
(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

±0.7% error over temperature
range

Update rate 100 ms or less

Signal Conditioning

Specified at +25 ºC (+77 ºF) unless
otherwise noted.

Hydro and Multimode Hydro Radial
Vibration

Frequency Response

Direct filter

Gap filter -3 dB at 0.05 Hz

0.104 Hz to 500 Hz

Rotor speed is 25 to 1,500 cpm.

Composite NX amplitude multiplied by the

percent change in gap from its
zero position
Specific for detecting Shear Pin
failure

Accuracy

Direct and
Gap

1X and NX Within ±0.33% of full-scale

Not 1X ±1% of full-scale typical

Composite ±1% of full-scale typical

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

typical
±1% 1X maximum
±3% NX maximum

±3% maximum

Hydro Air Gap and Multimode Air Gap

Instantaneous
Air Gap

Average Air
Gap

Provides instantaneous gap
measurements when the
pole-passing rate slows to
less than one pole/second

The monitor measures each
pole gap and averages the
values for all poles together
over one revolution.

Not 1X filter 0.25 to 128 times rotor speed

Constant Q notch filter
Minimum rejection in
stopband of -50 dB

1X and NX
vector filter

Constant Q Filter
Minimum rejection in
stopband of –50 dB

The N value in NX is selectable
between 2 and 20 (for
machine speeds of 25 cpm to
1,500cpm) or 2 to 50 (for
machine speeds of 25 cpm to
600 cpm).
1X and NX vector, Not 1X and
composite parameters are
valid for machine speeds per
selected NX value range.

Minimum Air
Gap

Maximum Air
Gap

Min Air Gap
Pole Number

Max Air Gap
Pole Number

4/16

The minimum pole gap
value in a revolution

The maximum pole gap
value in a revolution

The pole number detected
with the minimum gap value
in a revolution

The pole number detected
with the maximum gap
value in a revolution

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

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y

Accuracy

Average Air
Gap

Minimum Air
Gap

Maximum Air
Gap

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

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

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

Hydro Velocity and Multimode Hydro
Velocity

Frequency Response

Bias

Direct Low Mode: 0.1875 to 343.75 Hz,

1X and 2X
vector filter

Filter Quality

High-pass 4-pole (80 dB per decade, 24

Low-pass 2-pole (40 dB per decade,

Accuracy

Direct Within ±1% of full-scale

Low-pass filter

Low Mode: -3dB at 0.02 Hz
High Mode: -3dB at 0.07 Hz

-3dB
High Mode: 0. 75 to 1375 Hz, ­3dB

Constant Q Filter
Minimum rejection in
stopband of –51 dB

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

dB per octave)

12dB per octave)

typical
±2% maximum
Exclusive of filters

1X Amplitude Within ±1% of full-scale

typical
±2% maximum
Exclusive of filters

2X Amplitude Within ±1% of full-scale

typical
±2% maximum
Exclusive of filters

Hydro Thrust and Multimode Thrust

Frequency Response

Direct filter -3dB at 1.2 Hz

Gap filter -3dB at 0.4 1 Hz

Accuracy

Direct Within ±0.33% of full-scale

typical
±1% maximum

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

Filter Quality

High pass 4-pole (80 dB per decade,

Low pass 4-pole (80 dB per decade,

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.

24dB per octave)

24dB per octave)

5/16

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y



Direct Within ±0.33% of full scale

typical
±1% maximum
Exclusive of filters

Direct
Resultant

Pole Pass
Resultant

±1% of full-scale typical
±2% maximum

±2% of full-scale typical
±3% maximum

1X Amplitude Within ±0.33% of full scale

typical
±1% maximum
Exclusive of filters

2X Amplitude Within ±0.33% of full scale

typical
±1% maximum
Exclusive of filters

Hydro Stator End Winding (SEW)

Frequency Response

Direct 5.0 Hz to 800 Hz (-3dB

corners)

Bias voltage DC to 0.05 Hz (-3dB)

Pole Pass
Amplitude

Direct
Resultant

Pole Pass
Resultant

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

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

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

Multimode Hydro Dynamic Pressure

Frequency Response

Low mode 0.1875 Hz to 343.7500 Hz

High mode 0.75 Hz to 1375.00 Hz

Filter Quality

High pass 4-pole

(80 dB per decade,
24 dB per octave)

Low pass 4-pole

(80 dB per decade,
24 dB per octave)

Accuracy

Peak Direct
amplitud

RMS Direct
amplitude

Static Pressure ±0.87% of Full Scale





±1% of Full Scale
maximum

±2% of Full Scale
maximum

maximum

Frequency Ranges - Multimode
Acceleration Channel

The following table lists the frequency ranges
for the monitor under different options using
the Multimode Acceleration Channel type:

Accuracy

Direct ±1% of Full Scale maximum

Bias voltage ±1% of Full Scale maximum

Pole Pass
Amplitude

±2% of full-scale typical
±3% maximum

Output Type

RMS 10 to 30,000 10 to 20,000

Peak 3 to 30,000 3 to 20,000



6/16

Non-Integrated

(Hz)

Integrated

(Hz)

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y

Physical

Monitor Module (Main Board)

Dimensions
(Height x Width x
Depth)

Weight

I/O Modules

Dimensions
(Height x Width x
Depth)

Weight 0.20 kg (0.44 lb)



241.3 mm x 24.4 mm x

241.8 mm
(9.50 in x 0.96 in x 9.52 in)

0.91 kg (2.0 lb)

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

Rack Space Requirements

Monitor
Module

I/O Modules 1 full-height rear slot

1 full-height front slot

Alarms

Alarm
setpoints

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

Alarms are adjustable from
0 to 100% of full-scale for
each measured value
except when the full-scale
range exceeds the range of
the transducer. In this case,
the range of the transducer
will limit the setpoint.

Multimode
Hydro RV

Hydro Air Gap
and Multimode
Air Gap

Hydro Velocity
and Multimode
Hydro Velocity

Hydro Thrust
and Multimode
Thrust

Hydro
Acceleration
and Multimode
Acceleration

Hydro Stator
End Winding
(SEW)

Multimode
Hydro
Dynamic
Pressure

NX Amplitude
Composite
1X Phase Lag
NX Phase Lag

Direct
Gap
Not 1X Amplitude
1X Amplitude
NX Amplitude
Composite
1X Phase Lag

Average Air Gap
Minimum Air Gap

Direct
1X Amplitude
2X Amplitude
1X Phase Lag
2X Phase Lag

Direct
Gap

Direct
1X Amplitude
2X Amplitude
1X Phase Lag
2X Phase Lag

Direct
Pole Pass Amplitude
Direct Resultant
Pole Pass Resultant

Direct
Static Pressure
1X Amplitude
2X Amplitude
1X Phase Lag
2X Phase Lag

Alarm
accuracy

Hydro Radial
Vibration

Within 0.13% of the desired
value

Direct
Gap
Not 1X Amplitude
1X Amplitude

Alarm Time Delays

You can program alarm delays using

Rack Configuration Software.

Alert From 1 to 400 seconds in one

7/16

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y

second intervals

Danger From 1 to 400 seconds in one

second intervals

Multimode
channels

Standard
channels

You can set delays for each
measured value that has
alarm set points.

You can set one alert and
danger delay for the
channel.

8/16

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y

3500/46M Hydro Monitor Measured
Variables

Measured variables are used to monitor the
machine. The 3500/46M provides the following
measured variables:

Hydro Radial
Vibration

Multimode
Hydro RV

Hydro Air Gap Average Air Gap

Multimode Air
Gap

Direct
Gap
1X Amplitude
1X Phase Lag
NX Amplitude
NX Phase Lag
Not 1X Amplitude
Composite Amplitude

Direct
Gap
1X Amplitude
1X Phase Lag
NX Amplitude
Not 1X Amplitude
Composite Amplitude
Mode

Instantaneous Air Gap
Minimum Air Gap
Maximum Air Gap
Minimum Air Gap Pole
Number
Maximum Air Gap Pole
Number

Average Air Gap
Instantaneous Air Gap
Minimum Air Gap
Maximum Air Gap
Minimum Air Gap Pole
Number
Maximum Air Gap Pole
Number
Mode

Hydro Velocity Bias

1X Amplitude
1X Phase Lag
2X Amplitude
2X Phase Lag
Mode

Hydro Thrust Direct

Gap

Multimode
Thrust

Hydro
Acceleration

Multimode
Acceleration

Hydro Stator
End Winding
(SEW)

Multimode
Hydro
Dynamic
Pressure

Direct
Gap
Mode

Direct
Bias
1X Amplitude
1X Phase Lag
2X Amplitude
2X Phase Lag

Direct
Bias
1X Amplitude
1X Phase Lag
2X Amplitude
2X Phase Lag
Mode

Direct
Bias Voltage
Pole Pass Amplitude
Direct Resultant
Pole Pass Resultant

Direct
Static Pressure
1X Amplitude
1X Phase Lag
2X Amplitude
2X Phase Lag
Mode

Hydro Velocity Direct

Bias
1X Amplitude
1X Phase Lag
2X Amplitude
2X Phase Lag

Multimode Direct

9/16

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y

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

European Community Directive:

EMC Directive 2014/30/EU

Standards:

EN 61000-6-2 Immunity for

Industrial Environments

EN 61000-6-4 Emissions for

Industrial Environments

Electrical Safety

European Community Directive:

LV Directive 2014/35/EU

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

ATEX/IECEx

II 3 G

Ex nA nC ic IIC T4 Gc
Ex ec nC ic IIC T4/T5 Gc

T4 @ Ta= -20˚C to +65˚C
(-4˚F to +149˚F)
When installed per drawing 149243
or 149244.


Standards:

EN 61010-1

RoHS

European Community Directive:

RoHS Directive 2011/65/EU

Maritime

ABS - Marine and Offshore Applications

DNV GL Rules for Classification – Ships,
Offshore Units, and High Speed and Light
Craft

10/16

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y

Ordering Considerations

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

Application

3500/46M

Firmware

Version

3500/01

Software

Version

3500/02

Software

Version

3500/03

Software

Hydro 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  

Version



Application

Multimode applications
using hardware contacts to change monitor
modes

Multimode applications
using software commands to change monitor
modes

Multimode applications
incorporating the 3500/94 display

Applications requiring full multimode support
from System 1 software

3500/46M

Hardware

Revision S Multimode

3500/22

Firmware

3500/92

Firmware

  

System

I/O Modules

 1.32 1.16 

 1.60 2.30 

 1.32  6.0

1

11/16

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y

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. Y

125808-13 Multimode Recorder Output

Ordering Information

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

128702-01 Recorder External

and Mode Input External
Termination Block
Euro Style connectors

Termination Block
Euro Style connectors

Hydro Monitor
3500/46 - AA-BB

A: I/O Module Type

01

02 Prox/Velom I/O Module with External

03 Multimode Prox/Velom I/O Module with

04 Multimode Prox/Velom I/O Module with

05 Multimode Positive Input I/O Module

06 Multimode Positive Input I/O Module

B: Hazardous Area Approval Option

00 None

Prox/Velom I/O Module with Internal
Terminations

Terminations

Internal Terminations

External Terminations

with Internal Terminations

with External Terminations

128015-08

128015-11

128015-12 Multimode Positive Input

128015-13

128710-01

Prox/Velom External
Termination Block
Terminal Strip Connectors

Multimode Prox/Velom
External Termination Block
Terminal Strip connectors

External Termination Block
Terminal Strip connectors

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

Recorder External ET Block
Terminal Strip connectors

Cables

3500 Transducer (XDCR) to External
Termination (ET) Block Cable
129525 - AAAA-BB

01

02



CSA/NRTL/C (Class 1, Division 2)

ATEX/IECEx/CSA (Class 1, Zone 2)

External Termination Blocks

125808-08 Prox/Velom External

Termination Block
Euro Style connectors

125808-11 Multimode Prox/Velom

External Termination Block
Euro Style connectors

125808-12 Multimode Positive Input

External Termination Block
Euro Style connectors

A: I/O Cable Length

0005

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

B: Assembly Instructions

01 Not Assembled

02

13/16

5 feet (1.5 metres)

100 feet (30.5 metres)

Assembled

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y

3500 Recorder Output to External
Termination (ET) Block Cable (Non­Multimode)
129529 - AAAA-BB

A: I/O Cable Length

0005

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

B: Assembly Instructions

01 Not Assembled
02 Assembled



5 feet (1.5 metres)

100 feet (30.5 metres)

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 with
internal terminations

00580432 Euro Style connector header

10 pin
For use on I/O modules with
internal terminations

Spares

176449-06 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

169459-02 Multimode Prox/Velom I/O

Module with External
Terminations

169715-01 Multimode Positive Input I/O

Module with Internal
Terminations

169715-02 Multimode Positive Input I/O

Module with External

14/16

3500/46M Hydro Monitor
Datasheet 144408 Rev. Y

Graphs and Figures



1. Status LEDs
2. Buffered Transducer Outputs
3. Prox/Velom I/O Module with Internal Terminations
4. Prox/Velom I/O Module with External Terminations
5. 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. Y

Copyright 2020 Baker Hughes Company. All rights reserved.

Bently Nevada 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 not
make any representation as to the accuracy or completeness of the information and makes no warranties of any
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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
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

1631 Bently Parkway South, Minden, Nevada USA 89423

Phone: [phone] or 1.800.227.5514 (US only)

Bently.com

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