Bently Nevada 3500/70M Data sheet

3500/70M Recip Impulse Velocity Monitor

Datasheet

Bently Nevada Machinery Condition Monitoring

Description

The 3500/70M Recip Impulse Velocity Monitor is a 4-channel
device used as part of the reciprocating compressor
solutions package to monitor compressor crankcase and
crosshead vibration. The monitor accepts input from seismic
transducers, conditions the signal to derive vibration
measurements, and compares the conditioned signals with
user-programmable alarms.

You can program each channel using the 3500 Rack
Configuration Software to perform the following functions:

l Impulse Acceleration
l Acceleration 2
l Recip Velocity
l Low Frequency Recip Velocity

The monitor channels are programmed in pairs and can
perform up to two of the aforementioned functions at a time.
For example, channels 1 and 2 can perform one function
while channels 3 and 4 perform another or the same
function.

166766 Rev. M

The primary purpose of the 3500/70M Recip Impulse Velocity
Monitor is to provide the following:

l Machinery protection for reciprocating compressors by

continuously comparing monitored parameters
against configured alarm setpoints to drive alarms

l Essential reciprocating compressor machine

information for both operations and maintenance
personnel

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.

3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M

Impedance

Specifications

Inputs

Signal

Input impedance

Special inhibit

Power
consumption

Sensitivity

Impulse
acceleration

Acceleration 2

Recip velocity

Low Frequency
Recip velocity

Accepts from 1 to 4 proximity
probe signals.

10 kΩ acceleration input
>1 MΩ velocity input

Contact closure
5 Vdc @ 390μA typical

7.7 watts, nominal

0.51 – 11.72 mV/(m/s2)
5 – 115 mV/g

0.51 – 11.72 mV/(m/s2)
5 – 115 mV/g

3.54 – 22.64 mV/(mm/s)
90 – 575 mV/(in/s)

3.54 – 22.64 mV/(mm/s)
90 – 575 mV/(in/s)

Protection

Recorder Outputs

Recorder

Voltage
compliance

Load resistance 600 Ω maximum
Resolution 0.3662 µA maximum
Update rate <100 millisecond

Accuracy

Signal Conditioning

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

Each connector is short-circuit
protected.

+4 to +20 mA proportional to
monitor full-scale.
Selects one static data value
from each channel to be used for
that channel’s recorder value.

+12 Vdc maximum

Within ±0.05 mA.
±0.14 mA over temperature
range.

Outputs

Front Panel LEDs

Indicates when the 3500/70M

OK LED

TX/RX LED

Bypass LED

Transducer Power Supply

Voltage -22 Vdc minimum

Current

Output
impedance

Protection

Front Panel Buffered Outputs

Buffered
Transducer
Outputs

Output

Recip Impulse Velocity Monitor is
operating properly.

Indicates when the 3500/70M
Recip Impulse Velocity Monitor is
communicating with other
modules in the 3500 rack.

Indicates when the 3500/70M
Recip Impulse Velocity Monitor is
in Bypass Mode.

40 mA maximum
15 mA maximum on startup to
guarantee no fold back

20 Ω typical operating
1000 Ω typical under fold back
conditions

Foldback current

15.4 to 24.9 mA

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

550 Ω typical

Impulse Acceleration

Within ± 0.33% of full-scale

Accuracy

Band start

Band duration

Frequency Response

Bias filter

Not OK filter

Static values

Filter Quality

High-pass

Low-pass

typical,

± 1% maximum
Exclusive of filters

0 to 359°
1° resolution

1 to 360°
1° resolution

-3 dB at 0.01 Hz
1-pole
Low-Pass

-3 dB at 2400 Hz
1-pole
Low-Pass

Smoothing filter
8-revolution average value

4-pole
80 dB per decade
24 dB per octave

4-pole
80 dB per decade
24 dB per octave

2/13

3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M

Corner

Selection

High-pass 3 - 3000 Hz 10 - 3000 Hz

Low-pass 30 - 30000 Hz 40 - 30000 Hz

Peak 3 dB

Corner

RMS 3 dB

Corner

Acceleration 2

Within ± 0.33% of full-scale

Accuracy

Frequency Response

Bias filter

Not OK filter

Peak static values

RMS static values

Filter Quality

High-pass

Low-pass

Corner

Selection

High-pass

Low-pass

typical
± 1% maximum
Exclusive of filters

-3 dB at 0.01 Hz
1-pole
Low-Pass

-3 dB at 2400 Hz
1-pole
Low-Pass

-3 dB at 0.3 Hz
1-pole
Low-Pass

-3 dB at 0.1 Hz
1-pole
Low-Pass

4-pole
80 dB per decade
24 dB per octave

4-pole
80 dB per decade
24 dB per octave

Pk 3 dB

Corner

3 - 3000 Hz10 - 3000

30-30000
Hz

RMS 3 dB

Corner

Hz

40 ­30000 Hz

Integrate

3dB

Corner

3-3000 Hz

40-20000
Hz

Recip Velocity

Accuracy

Velomitor

Frequency Response

Bias filter

Not OK filter

Integration filter

RMS static values

Peak static values

1X & 2X Vector
Filter

Filter Quality

High-pass

Low-pass

Corner

Selection

Pk 3 dB

Corner

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

Additional accuracy degradation
occurs when full scale signal
levels are low:
Full Scale 0-0.5: ±3% typical
Full Scale 0-1.0: ±2% typical
Full Scale 0-2.0: ±1% typical

-3 dB at 0.01 Hz
1-pole
Low-Pass

-3 dB at 2400 Hz
1-pole
Low-Pass

-3 db at 0.34 Hz
1-pole
Low-Pass

-3 dB at 0.1 Hz
1-pole
Low-Pass

-3 dB at 0.3 Hz
1-pole
Low-Pass

Constant Q filter with bandwidth
= ±3% running speed
Q = 16.7

4-pole
80 dB per decade
24 dB per octave

2-pole
40 dB per decade
12 dB per octave

RMS 3 dB

Corner

Integrate

3dB

Corner





High-pass 1- 400 Hz 10-400 Hz 3-400 Hz

Low-pass

40-5500
Hz

60-5500
Hz

40-5500
Hz









3/13

3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M

Low Frequency Recip Velocity

Within ± 0.33% of full-scale

Accuracy

Velomitor

Frequency Response

Bias filter

Not OK filter

Integration filter

RMS static values

Peak static values

1X & 2X Vector
Filter

Filter Quality

High-pass

Low-pass

Corner

Selection

High-pass 0.750 - 100 Hz 0.750 - 100 Hz

Low-pass 10 - 1375 Hz 15 - 1375 Hz

typical
± 1% maximum
Exclusive of filters

Additional accuracy degradation
occurs when full scale signal
levels are low:
Full Scale 0-0.5: ±3% typical
Full Scale 0-1.0: ±2% typical
Full Scale 0-2.0: ±1% typical

-3 dB at 0.01 Hz
1-pole
Low-Pass

-3 dB at 2400 Hz
1-pole
Low-Pass

-3 db at 0.34 Hz
1-pole
Low-Pass

-3 dB at 0.1 Hz
1-pole
Low-Pass

-3 dB at 0.3 Hz
1-pole
Low-Pass

Constant Q filter with bandwidth
= ±3% running speed
Q = 16.7

4-pole
80 dB per decade
24 dB per octave

2-pole
40 dB per decade
12 dB per octave

Peak and

Integrate 3dB

Corner

RMS 3 dB

Corner

Rack Space Requirements

Monitor 1 full-height front slot
I/O Modules 1 full-height rear slot

Physical

Monitor Module (Main Board)

Dimensions
(Height x Width x
Depth)

Weight 0.91 kg (2.0 lb)

I/O Modules (non-barrier)

Dimensions
(Height x Width x
Depth)

Weight 0.20 kg (0.44 lb)

I/O Modules (barrier)

Dimensions
(Height x Width x
Depth)

Weight 0.46 kg (1.01 lb)

241.3 mm x 24.4 mm x 241.8
mm
(9.50 in x 0.96 in x 9.52 in)

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

241.3 mm x 24.4 mm x 163.1
mm
(9.50 in x 0.96 in x 6.42 in)

Alarms

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.

Alarm Setpoints

Accuracy of
alarm setpoints

Alarm Time Delays

You can program alarm delays using 3500
Rack Configuration Software.

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

Within 0.13% of the desired value

4/13

Alert

Danger

From one to 60 seconds in one
second intervals

0.1 seconds (nominal) or from
one to 60 seconds in one second
intervals

3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M

Static Values

Static values are measurements used to
monitor the machine. The 3500/70M Recip
Impulse Velocity Monitor returns static values
from the following channels:

Direct

Impulse
Acceleration

Acceleration 2

Recip Velocity

Low Frequency
Recip Velocity

Bias Voltage
Six user-adjustable crank angle
bands with peak or RMS
acceleration in the band

Direct
1X Amplitude
2X Amplitude
1X Phase
2X Phase
Bias Voltage

Direct
1X Amplitude
2X Amplitude
1X Phase
2X Phase
Bias Voltage

Direct
1X Amplitude
2X Amplitude
1X Phase
2X Phase
Bias Voltage

Barrier Parameters

The following parameters apply to CSA-NRTL/C
and CENELEC approvals.

Proximitor Barrier

Vmax (PWR) = 26.80

V (SIG) = 14.05 V
Circuit
Parameters

Channel
Parameters
(Entity)

Seismic Barrier

Circuit
Parameters

Channel
Parameters
(Entity)

Imax (PWR) = 112.8 mA

(SIG) = 2.82 mA

Rmin (PWR) = 237.6 Ω

(SIG) = 4985 Ω

Vmax = 28.0 V

Imax = 115.62 mA

Rmin (PWR) = 237.6 Ω

(SIG) = 4985 Ω

Vmax (PWR) = 27.25 V

Imax (PWR) = 91.8 mA

Rmin (PWR) = 297 Ω

Vmax = 27.25 V

Imax = 91.8 mA

Rmin (PWR) = 297 Ω

Bias voltage contains no information
about the condition of the machinery
being monitored. It is provided for
monitor system diagnostics.



Environmental Limits

When used with Internal /

External Termination Proximitor /

Seismic I/O Module:

-30°C to +65°C

Operating
Temperature

Storage
Temperature

Humidity

(-22°F to +149°F)

When used with Proximitor /

Seismic Internal Barrier I/O

Module (Internal Termination)

0°C to +65°C

(32°F to +149°F)

-40°C to +85°C

(-40°F to +185°F)

95%

Non-condensing

5/13

3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M

Hazardous Area Approvals

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

Standards:

EN 61010-1

RoHS

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;

When used with
I/O module
ordering options
without internal
barriers

When used with
I/O module
ordering options
with internal
barriers

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.

Class I, Zone 2: AEx/Ex nA nC ic
[ia Ga] IIC T4 Gc;
Class I, Zone 2: AEx/Ex ec nC ic
[ia Ga] IIC T4 Gc;
Class I, Division 2, Groups A, B, C,
and D (W/ IS Output for Division

1)

T4 @ Ta= -20˚C to +65˚C (-4˚F
to +149˚F)
When installed per drawing

138547.

ATEX/IECEx

II 3 G

When used with
I/O module
ordering options
without internal
barriers

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

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

When used with
I/O module
ordering options
with internal
barriers



6/13

II 3(1) G

Ex nA nC ic [ia Ga] IIC T4 Gc;
Ex ec nC ic [ia Ga] IIC T4 Gc;

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

138547.

3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M

Ordering Considerations

l For I/O modules with External

Terminations, order the External
Termination Blocks and cable separately
for each I/O module.

l For the Internal Barriers, refer to the 3500

Internal Barrier datasheet, document

141495.

l External Termination Blocks cannot be

used with Internal Termination I/O
Modules.

The lower limit for machine speed is 60
RPM in standard product. For machine
speeds down to 30 RPM, modification
135M8137-01 is required.

Software Compatibility

3500/01
Configuration
Software

3500/02 Data
Acquisition
Software

3500/03
Operator Display
Software

System1 Software Version 6.90 or later

Version 5.2 or later

Version 2.50 or later

Version 1.50 or later

Firmware Compatibility

3500/70M
Firmware

3500/22M TDI
Firmware

3500/22M USB TDI
Firmware

Version 4.21 or later

Version 1.75 or later

Version 4.05 or later

7/13

3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M

Cables

Ordering Information

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

Bently.com.

Recip Impulse / Velocity Monitor
3500/70M - AA-BB

A: I/O Module Type

01

02

03 Internal Barrier, Four Accelerometers

04

05 Internal Barrier, Four Velomitors
B: Agency Approval

00 None
01 CSA / NRTL / C (Class 1, Division 2)
02 ATEX/ IECEx/ CSA (Class 1, Zone 2)



External Termination Blocks

Part Number Description

128702-01

128710-01

125808-08

128015-08

Prox/Velom I/O Module with Internal
Terminations

Prox/Velom I/O Module with External
Terminations

Internal Barrier, Two Accelerometers, Two
Velomitors

Order the Earthing Module for each rack
with internal barriers.

Recorder External Termination
Block
Euro Style connectors

Recorder External Termination
Block
Terminal Strip connectors

Proximitor / Velomitor External
Termination Block
Euro Style connectors

Proximitor / Velomitor External
Termination Block
Terminal Strip connectors

3500 Transducer (XDCR) to External
Termination (ET) Block Cable

129525 - AAAA-BB

A: I/O Cable Length
0005 5 feet (1.5 meters)
0007 7 feet (2.1 meters)
0010 10 feet (3.0 meters)
0025 25 feet (7.6 meters)
0050 50 feet (15.2 meters)
0100 100 feet (30.5 meters)
B: Assembly Instructions
01 Not assembled
02 Assembled

3500 Recorder Output to External
Termination (ET) Block Cable

129529-AAAA-BB

A: I/O Cable Length
0005 5 feet (1.5 meters)
0007 7 feet (2.1 meters)
0010 10 feet (3.0 meters)
0025 25 feet (7.6 meters)
0050 50 feet (15.2 meters)
0100 100 feet (30.5 meters)
B: Assembly Instructions
01 Not assembled
02 Assembled







8/13

3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M

Spares

Part Number Description

176449-09

166226-01

135489-01

135489-02

135489-03

140471-01

140482-01

00561941

00580434

00580432

00502133

3500/70M Recip Impulse Velocity
Monitor

3500/70M Recip Impulse Velocity
Monitor User Manual

I/O Module with Internal Barriers,
Internal Terminations
4 x Prox/Accel

I/O Module with Internal Barriers,
Internal Terminations
2 x Prox/Accel and
2 x Velomitor

I/O Module with Internal Barriers,
Internal Terminations
4 x Velomitor

Prox/Velom I/O Module with
Internal Terminations

Prox/Velom I/O Module with
External Terminations

3500/70M Prox/Velom I/O
Module ten-pin connector shunt

Internal I/O Module connector
header
Euro Style, 8 pin
For I/O modules 128229-01 and
138708-01

Internal I/O Module connector
header
Euro Style, 10 pin
For I/O modules 128229-01,
138708-01

Internal I/O Module connector
header
Euro Style, 12 pin

9/13

3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M

Graphs and Figures

1. Status LEDs
2. Buffered Transducer Outputs
3. Prox/Velom I/O Module, Internal Termination, 140471-01
4. Prox/Velom I/O Module, External Termination, 140482-01

Figure 1: 3500/70M Front and Rear Views

10/13

3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M



Figure 2: Side View of I/O Modules

The I/O modules with internal or external terminations have the same jumpers.





11/13

3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M

1. Barrier I/O module to connect four Accelerometer sensors,

135489-01

2. Barrier I/O module to connect two Accelerometer sensors

and two Velomitor sensors, 135489-02

3. Barrier I/O module to connect four Velomitor sensors,

135489-03

Figure 3: Barrier I/O Modules

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3500/70M Recip Impulse Velocity Monitor
Datasheet 166766 Rev. M

Copyright 2020 Baker Hughes Company. All rights reserved.

Bently Nevada, Orbit Logo, Proximitor and Velomitor 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

13/13