Bently Nevada 3500/72M Data sheet

3500/72M Recip Rod Position Monitor

Datasheet

Bently Nevada Machinery Condition Monitoring

Description

The four-channel 3500/72M Recip Rod Position Monitor
accepts input from proximity transducers, conditions the
signal to provide dynamic and static position measurements,
and compares the conditioned signals with user­programmable alarms.

Each channel, depending on how you configure it, typically
conditions its input signal to generate various parameters
called measured values.

Use the 3500 Rack Configuration Software to:

l Configure alert setpoints for each active measured

value and danger setpoints for any two of the active
measured values.

l Protect reciprocating compressors by continuously

comparing monitored parameters against configured
alarm setpoints to display alarms and trigger relays, if
needed.

l Monitor the condition of essential reciprocating

compressor machinery.

146478 Rev. H

The monitor channels are programmed in pairs and
can perform up to two 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.

The 3500/72M Recip Rod Position Monitor meets API 618
requirements for reciprocating compressors. It measures:

l Rod position
l Rod drop
l Hyper-compressor

3500/72M Recip Rod Position Monitor
Datasheet 146478 Rev. H

Data Values

The 3500/72M Recip Rod Position Monitor

Specifications

returns the following data values from
measurements used to monitor the machine:

Inputs

Signal

Input Impedance 10 kΩ

Nominal Scale Factor

Rod Position

Rod Position 2

Rod Drop

Hyper
Compressor

Power
Consumption

Accepts from 1 to 4 proximity
probe signals

0.79 mV/µm (20 mV/mil),

3.94 mV/µm (100 mV/mil) or

7.87 mV/µm (200 mV/mil)

3.94 mV/µm (100 mV/mil) or

7.87 mV/µm (200 mV/mil)

3.94 mV/µm (100 mV/mil) or

7.87 mV/µm (200 mV/mil)

3.94 mV/µm (100 mV/mil) or

7.87 mV/µm (200 mV/mil)

7.7 watts, nominal

Outputs

Front Panel LEDs

Indicates when the Recip Rod

OK LED

TX/RX LED

Bypass LED

Front Buffered Outputs

Buffered
Transducer
Outputs

Output
Impedance

Transducer Power
Supply

Position Monitor is operating
properly.

Indicates when the Recip Rod
Position Monitor is
communicating with other
modules in the 3500 rack.

Indicates when the Recip Rod
Position Monitor is in Bypass
Mode.

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

Each connector is short-circuit
protected.

510 Ω

-24 Vdc

Rod Position
Single Channel

Rod Position
Single 2 Channel

Rod Position Pair
Channel

Rod Position Pair
2 Channel

Rod Drop
Channel

Hyper Channel

Position Magnitude,
Position Angle,
Crank Angle,
Pk-Pk Amplitude,
Gap,
1X Amplitude,
Not 1X Amplitude,
2X Amplitude

Pk-Pk Amplitude
Position Magnitude
Position Angle
Crank Angle
Gap
Average Piston Position
Instantaneous Piston Position
Instantaneous Probe Gap

Position Magnitude,
Position Angle,
Crank Angle,
Pk-Pk Amplitude,
Gap,
1X Amplitude,
Not 1X Amplitude,
2X Amplitude

Pk-Pk Amplitude
Position Magnitude
Position Angle
Crank Angle
Gap
Average Piston Position
Instantaneous Piston Position
Instantaneous Probe Gap

Average Piston Position,
Average Probe Gap,
Instantaneous Piston Position,
Instantaneous Probe Gap

Pk-Pk Displacement,
Gap,
1X Amplitude,
Not 1X Amplitude,
2X Amplitude

2/11

3500/72M Recip Rod Position Monitor
Datasheet 146478 Rev. H

Signal Conditioning

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

Rod Position 2 (Single and Pair) Channels

Frequency Response

Peak-Peak filter Fixed 1 Hz to 600 Hz
Gap filter -3 dB at 0.09 Hz
Average piston

position

Accuracy

Peak-Peak
Amplitude

Position
magnitude

Rod Position
Angle
(paired only)

Position Crank
Angle

Gap

Average piston
position

Instantaneous
piston position

Instantaneous
piston gap

Rod Position Single and Pair Channels

Peak-Peak filter Fixed 1 Hz to 600 Hz
Gap filter -3 dB at 0.09 Hz

Not 1X filter

1X and 2X vector
filter

Fixed 1 Hz to 600 Hz

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

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

Within ±1° typical
±3° maximum

Within ±1° typical
±3° maximum

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

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

Frequency Response

Constant Q Notch filter
Minimum rejection in stop-band
of 34.9 dB over frequency range
of 60 cpm to 15.8 times running
speed

Constant Q Filter
Minimum rejection in stopband

Frequency Response

of 57.7 dB

1X and 2X Vector and Not 1X parameters
are valid for machine speeds of 60 cpm
to 2130 cpm.

Accuracy

Position
magnitude
(direct)

Gap

1X Amplitude

2X Amplitude

Pk-Pk Amplitude

Not 1X Amplitude Within ±3.0% of full scale typical
Position Crank

Angle
Rod Position

Angle
(paired only)

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

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

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

Within ±1° typical
±3° maximum

Within ±1° typical
±3° maximum

Rod Drop Channels

Frequency Response

Average piston
position (direct)

Average Gap -3 dB at 0.09 Hz

Accuracy

Average piston
position (direct)

Average Gap

Instantaneous
piston position

Instantaneous
probe Gap

Fixed 1 Hz to 600 Hz

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

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

3/11

3500/72M Recip Rod Position Monitor
Datasheet 146478 Rev. H

Hyper Channels

Frequency Response

Peak-Peak filter Fixed 1 Hz to 600 Hz
Gap filter -3 dB at 0.09 Hz

Constant Q Notch filter
Minimum rejection in stop-band

Not 1X filter

1X Vector filter

2X Vector filter

of 34.9 dB over frequency range
of 60 cpm to 15.8 times running
speed

Constant Q filter
Minimum rejection in stop-band
of 57.7 dB

Constant Q filter
Minimum rejection in stop-band
of 57.7 dB

1X and 2X Vector and Not 1X parameters
are valid for machine speeds of 60 cpm
to 2130 cpm.

Accuracy

Peak-Peak
magnitude

Gap

1X Amplitude

2X Amplitude

Not 1X Amplitude

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

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

Within ±0.33% of full-scale
typical

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)

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)

Monitor Module (Main Board)

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

Rack Space Requirements

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

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

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

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

Alarm Time Delays

You can program alarm delays using 3500
Rack Configuration Software.

Alert

From one to 60 seconds in one
second intervals

4/11

3500/72M Recip Rod Position Monitor
Datasheet 146478 Rev. H

0.1 seconds (nominal) or from

Danger

Timed OK
Channel Defeat

one to 60 seconds in one second
intervals

OK Channel defeat is disabled for
all Rod Position and Rod Drop
configurations.

As a hyper-compressor monitor,
when both transducers are NOT
OK, the monitor issues a Danger
alarm immediately.

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

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

5/11

3500/72M Recip Rod Position Monitor
Datasheet 146478 Rev. H

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;

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

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

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



II 3 G


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.

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.

6/11

3500/72M Recip Rod Position Monitor
Datasheet 146478 Rev. H

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 Internal Barriers, refer to the 3500

Internal Barrier Datasheet (document

141495).

l The Recip Rod Position Monitor requires

version 3.20 or higher of the 3500 Rack
Configuration Software.

l Rod Position Single 2 and Rod Position

Pair 2 channel types require Rack Config
release 6.0 or later.

The lower limit for machine speed is 60
RPM in the standard product. For
machine speeds down to 30 RPM,
modification 135M8199-01 is required.



Ordering Information

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

Bently.com.

Rod Position Monitor
3500/72M - AA-BB

External Termination Blocks

Part Number Description

Proximitor / Velomitor External

125808-08

128015-08

128702-01

128710-01

Cables

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

A: I/O Cable Length
0005 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

Termination Block
Euro Style connectors

Proximitor / Velomitor External
Termination Block
Terminal Strip Connectors

Recorder External Termination
Block
Euro Style Connectors

Recorder External Termination
Block
Terminal Strip Connectors

A: I/O Module Type
01 I/O Module with Internal Terminations
02 I/O Module with External Terminations

I/O Module with Internal Barriers and Internal

03

Terminations

B: Hazardous Area Approval Option
00 None
01 CSA/NRTL/C (Class 1, Division 2)

ATEX/IECEx/CSA (Class 1, Zone 2)

02



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

A: I/O Cable Length
0005 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

7/11

3500/72M Recip Rod Position Monitor
Datasheet 146478 Rev. H

01 Not Assembled
02 Assembled



Spares

Part Number Description

176449-08

140471-01

00580434

140482-01

135489-01

00580441

00502133

146479-01

3500/72M Recip Rod Position
Monitor

I/O Module with Internal
Terminations

Internal I/O Module connector
header
Euro Style, 8-pin, green
Used with I/O modules 140471-01

I/O Module with External
Terminations

I/O Module with Internal Barriers
and Internal Terminations

Internal I/O Module connector
header
Euro Style, 3-pin, green
Used with I/O modules 135489­01 and 140471-01

Internal I/O Module connector
header
Euro Style, 12 pin, blue
Used with I/O modules 135489­01

3500/72M Recip Rod Position
Monitor User Manual



8/11

3500/72M Recip Rod Position Monitor
Datasheet 146478 Rev. H

Graphs and Figures

Figure 1: Legacy Front and Rear Views of 3500/72M Recip Rod Position Monitor

1. 3500/72M Front View
2. Status LEDs
3. Buffered Transducer Outputs
4. I/O Modules Rear Views
5. Barrier I/O Module, Internal Termination
6. I/O Module, Internal Termination

7. I/O Module, External Termination

9/11

3500/72M Recip Rod Position Monitor
Datasheet 146478 Rev. H

Figure 2: Updated Rear View of 3500/72M I/O Modules

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

10/11

3500/72M Recip Rod Position Monitor
Datasheet 146478 Rev. H

Copyright 2020 Baker Hughes Company. All rights reserved.

Bently Nevada, Orbit Logo, Velomitor 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

11/11