3500/77M Recip Cylinder Pressure Monitor
Datasheet

Bently Nevada Machinery Condition Monitoring

147485 Rev. UDescription
The 3500/77M Recip Cylinder Pressure Monitor is a 4-channel
monitor that accepts input from Bently Nevada approvedpressure transducers, conditions the signal to make variouspressure measurements for reciprocating compressors, andcompares the conditioned signals with user-programmable
alarms.
The primary purpose of the 3500/77M monitor is to provide:llMachinery protection by continuously comparing
monitored parameters against configured alarm
setpoints to drive alarms.
Essential machine information for operations andmaintenance personnel.

Depending on configuration, each channel typicallyconditions its input signal to provide various parameters
called measured variables. Users can configure Alert
setpoints for each active measured variable and Danger
setpoints for any two of the active measured variables.
Each channel of the 3500/77M will provide eight measured
variable values that relate to cylinder pressure operation. The
five values that relate to a single chamber are as follows:lllll

Discharge Pressure
Suction Pressure
Maximum Pressure
Minimum PressureCompression Ratio

3500/77M Recip Cylinder Pressure Monitor
Datasheet

147485 Rev. U

Three measured variables combine one ormore channel values with configured
mechanical parameters to compute theirvalue:lll

Peak Rod Compression
Peak Rod Tension
Degree of Rod Reversal

For more information on the 3500/77M RecipCylinder Pressure Monitor, refer to the User
Guide (document 146282).

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3500/77M Recip Cylinder Pressure Monitor
Datasheet

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Measured VariablesSpecifications
InputsCylinderPressureAccepts 1 to 4 channels of Bently
Nevada approved positive
voltage 3rd-party pressuretransducers (psia)

SignalInput Impedance

Scale Factor
range†

95,000 mV/psi for 100 psia

range†

38,000 mV/psi for 250 psia

range†

19,000 mV/psi for 500 psia

range†

9,500 mV/psi for 1000 psia

range†

3,800 mV/psi for 2500 psia

range†

1,900 mV/psi for 5000 psia

range†

950 mV/psi for 10,000 psia

50 kΩ

PowerConsumption

7.8 Watts with transducer
supplies at full load.

Front Panel LEDs

Signal Conditioning

Pressure
AccuracyInternal/
External
Termination
CylinderPressure I/OOutputs†All pressure transducers will be
supplied with scale factor
specifications that include
pressure/voltage values at twopoints. The above data assumes +0.5
Vdc at 0 psia and +10.0 Vdc at thefull-range psia value.

Frequency
Response

Discharge Pressure, Suction
Pressure, Maximum Pressure,
Minimum Pressure,Compression Ratio, Peak Rod
Compression, Peak Rod
Tension, Degree of Rod
Reversal

0 to 5.5 kHz on all configured
pressure channels
Within ± 0.5% of pressuretransducer full-range (9.5 Volts:
From +0.5 to +10.0 Volts) @+25°C (77º F)

OK LED

Indicates when the3500/77M is operating
properly.

TX/RX LED

Indicates when the
3500/77M iscommunicating with othermodules in the 3500 rack.

Bypass LED

Indicates when the
3500/77M is in BypassMode.

BufferedTransducer
Outputs

The front of each monitor
has one coaxial connector
for each channel. Eachconnector is short-circuit
protected.

The Buffered Transducer Outputs onmonitors using the Cylinder Pressure
I/O module will be inverted and offset
by -2.265 Vdc.

Within ± 1.0% of pressuretransducer full-range (9.5 Volts:
From +0.5 to +10.0 Volts) over–30°C to +65°C (-22ºF to 150ºF)

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Datasheet

OutputImpedance

550 ΩTransducer
Power Supply+23.0 ± 0.8 Vdc with 24.5
ma current limiting oneach channel.

147485 Rev. U

Environmental Limits
Operating Temperature
When used with
Internal/External
Termination
Cylinder Pressure
I/O Module:-30°C to +65°C(-22°F to +150°F)

Storage
Temperature-40°C to +85°C

Humidity

95%, non-condensing(-40°F to +185°F)

PhysicalMonitor Module241.3 mm x 24.4 mm xDimensions (Height 241.8 mmx Width x Depth)(9.50 in x 0.96 in x 9.52in)

Weight0.91 kg (2.0 lb.)

I/O Modules
241.3 mm x 24.4 mm xDimensions (Height 99.1 mmx Width x Depth)(9.50 in x 0.96 in x 3.90in)

Weight0.20 kg (0.44 lb.)

Rack Space Requirements
Monitor Module

1 full-height front slot

I/O Modules

1 full-height rear slot

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3500/77M Recip Cylinder Pressure Monitor
Datasheet

147485 Rev. U

Hazardous Area Approvals

Compliance and Certifications

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

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

For additional technicaldocumentation, please log in tobntechsupport.com and access theBently Nevada Media Library.

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

cNRTLusClass 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;

EMC
European Community Directive:

T4 @ Ta= -20˚C to +65˚C (-4˚F to +149˚F)
When installed per drawing 149243 or149244.

EMC Directive 2014/30/EU
Standards:

ATEX/IECEx

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

II 3 GEx nA nC ic IIC T4 Gc
Ex ec nC ic IIC T4 Gc

Electrical Safety

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

European Community Directive:
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

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3500/77M Recip Cylinder Pressure Monitor
Datasheet

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Ordering Information

Ordering Considerations

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

GeneralThe 3500/77M Module requires the following (orlater) firmware and software revisions:llll

For additional technicaldocumentation, please log in tobntechsupport.com and access theBently Nevada Media Library.

3500/77M Module Firmware Revision L
3500/01 Software – Version 3.00
3500/02 Software – Version 2.30
3500/03 Software – Version 1.30

External Termination Blocks cannot be usedwith Internal Termination I/O Modules.

Cylinder Pressure Monitor

When ordering I/O Modules with External
Terminations, the External Termination Blocks
and Cables must be ordered separately.

3500/77M-AA-BB
A: I/O Module TypeThe lower limit for machine speed is 60 RPM in
the standard product. For machine speeds
down to 30 RPM, modification 135M8200-01 isrequired.

03

Cylinder Pressure I/O with InternalTerminations.

04

Cylinder Pressure I/O with External
Terminations

B: Agency Approval Option

6/900

None01cNRTLus02

ATEX/IECEx/CSA

3500/77M Recip Cylinder Pressure Monitor
Datasheet

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External Termination Blocks
PartNumberPart
NumberDescription

Description

143729-01

Cylinder Pressure I/O Modulewith Internal Terminations for
Bently Approved Third Party
Pressure Transducers

143737-01

Cylinder Pressure I/O Modulewith External Terminations for
Bently Approved Third Party
Pressure Transducers

00580434

Internal I/O Module connector
header, Euro Style, 8 pin. Used
on I/O modules 143729-01.

00580441

Internal I/O Module connector
header, Euro Style, 3 pin. Used
on I/O modules 143729-01.

146973-01

Recip Multi-Event Wheel Kit

A: Cable Length

145732-01

Recip Multi-Event Wheel

0005

5 feet (1.5 metres)

146622-01

Recip Multi-Event Wheel Stud0007

7 feet (2.1 metres)
165855-XX

Recip Cylinder Pressure
Transducer(See 165855 datasheet)283615

MTL 7796+ External Barrier (SeeField Wiring Dwg 147729)(022000812 MTL 796(+) ExternalBarrier is discontinued)

115M1270XX

Custom Band Type, dual track114M1640XX

Custom Band Type, single track

111M8664-01

Installation manual for the bandtype

166M4363

Connector Header,
Push-in-Spring Type
(Alternative for PN 00580441)

166M2389

Connector Header,
Push-in-Spring Type
(Alternative for PN 00580434)

12580810

Cylinder Pressure External
Termination Block (Euro Styleconnectors).

Cylinder Pressure External
128015-10 Termination Block (Terminal Stripconnectors).

Cable
3500 Transducer Signal to External
Termination Block Cable
129525-AAAA-BB

0010

10 feet (3 metres)

0025

25 feet (7.5 metres)0050

50 feet (15 metres)

0100

100 feet (30.5 metres)

B: Assembly Instructions
01

Not Assembled

02

Assembled

Spares and Accessories
Part
Number176449-07

Description
3500/77M Cylinder PressureMonitor.

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3500/77M Recip Cylinder Pressure Monitor
Datasheet

147485 Rev. U

Graphs and Figures

1. Main 3500/77M Cylinder Pressure Monitor Module (frontview).
2. Status LEDs.
3. Buffered transducer outputs. These provide an unfilteredoutput for each of the four transducers. All are short circuit
protected.
4. I/O module rear views.
5. Cylinder Pressure I/O Module, Internal Termination.
6. Cylinder Pressure I/O Module, External Termination.
Figure 1: 3500/77M Front and Rear View

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3500/77M Recip Cylinder Pressure Monitor
Datasheet

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Copyright 2024 Baker Hughes Company. All rights reserved.

Bently Nevada, M2 and Orbit Logo are registered trademarks of Bently Nevada, a Baker Hughes business, in theUnited States and other countries. The Baker Hughes logo is a trademark of Baker Hughes Company. All otherproduct 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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