3500/50M Tachometer Module
Datasheet

Bently Nevada Machinery Condition Monitoring141538 Rev. TDescription
The 3500/50M Tachometer Module is a 2-channel modulethat accepts input from proximity probes or magnetic
pickups to determine shaft rotative speed, rotor acceleration,or rotor direction. The module compares thesemeasurements against user-programmable alarm setpoints
and generates alarms when the setpoints are violated.
The Tachometer Module is programmed using the 3500 Rack
Configuration software. The following configuration options
are available:llll

Speed Monitoring, Setpoint Alarming and Speed Band
Alarming
Speed Monitoring, Setpoint Alarming and Zero Speed
Notification
Speed Monitoring, Setpoint Alarming and Rotor
Acceleration Alarming
Speed Monitoring, Setpoint Alarming and Reverse
Rotation Notification

The 3500/50M Tachometer Module can be configured tosupply conditioned Keyphasor signals to the backplane of the3500 rack for use by other monitors. Therefore, you don't needa separate Keyphasor module in the rack.
The 3500/50M Tachometer Module has a peak hold featurethat stores the highest speed, the highest reverse speed, orthe number of reverse rotations that the machine hasreached. You can reset the peak values.
Bently Nevada offers an Overspeed Protection
System (Product 3701/55).

3500/50M Tachometer Module
Datasheet141538 Rev. TWarning
WARNINGPRODUCT MISUSE
Risk of personal injury or equipment damage.
Do not use the 3500/50M Tachometer Module
independently or as a component of a speed
control or an overspeed protection systembecause it does not provide protective
redundancy or the response speed needed forreliable operation as a speed control or overspeed
protection system.
The analog proportional output is suitable for data
logging, chart recording, or display purposes only.
Speed alert setpoints are suitable for annunciation
purposes only.
Magnetic Pickups:
Do not use magnetic pickups for the reverse
rotation option or zero speed option. Otherwise,
false indications of rotation direction may occur.
The transducers do not provide a clean edge forthe detection circuit during low speeds.

2/11

3500/50M Tachometer Module
Datasheet141538 Rev. T

Buffered Transducer

Specifications

The front of each module has
one coaxial connector foreach channel.

InputsEach 3500/50M Tachometer
Module accepts up to twotransducer signals fromproximity probe transducers
or magnetic pickups.

SignalOutputs

Buffered outputs are available
at the I/O module via Eurostyle connectors.

+10.0 V to -24.0 V
Input signal
range

Signals exceeding this range
are limited internally by themodule.

Input
impedance

20 k Ω (standard)
40 k Ω (TMR)
7.15 k Ω (Internal Barrier)Power
consumption

5.8 Watts, typical

550 ΩTransducer
Power Supply

24 Vdc, 40 mA maximum perchannelValues are proportional tomodule full-scale range (rpmor rpm/min).
RecorderVoltageCompliance(currentoutput)

Front Panel LEDs
Indicates when the 3500/50M
Tachometer Module isoperating properly.

TX/RX LED

Indicates when theTachometer Module iscommunicating with othermodules in the 3500 rack.

Bypass LED

Indicates when the
Tachometer Module is in
Bypass Mode.

Individual recorder values areprovided for each channel.
Monitor operation isunaffected by short circuits onrecorder outputs.

Restrictions may apply tomagnetic pickups (seeWarning on page 2).

Outputs

OK LED

OutputImpedance+4 to +20 mA

Accepts 1 to 2 proximity
transducer signalsTransducers

Each connector is short circuitand ESD protected.

Resolution

0 to +12 Vdc range across load
Load resistance is 0 to 600 Ω0.3662 µA per bit ±0.25% error
at room temperature ±0.7%error over temperature range
Update rate approximately
100 ms3/11

3500/50M Tachometer Module
Datasheet141538 Rev. T

Signal Conditioning

Hysteresis

Specified at +25ºC (+77ºF)

AlarmsThe 3500/50M Tachometer
Module supports 1 to 255
events per revolution for
Rotor Acceleration and Zero
Speed channel types.

Alarm 1 levels (setpoints)
can be set for each value
measured by theTachometer.

All other channel types
support 0.0039 to 255 events
per revolution.
Speed Input

AlarmSetpoints

All channel types support amaximum full scale range of99,999 rpm and a maximum
input frequency of 20 kHz.

Alarms are adjustable andcan normally be set from 0
to 100% of full scale for eachmeasured value.

Minimum input frequency forpassive magnetic pickups is
3.3 Hz.

RPM/MinAccuracyLess than 100 rpm = ± 0.1 rpm
100 to 10,000 rpm = ±1 rpm
10,000 to 99,999 rpm = ±0.01% of true shaft speed

ManualThreshold

Alarm Time
DelaysProgrammable alarm delays
for Alarm 1 and Alarm 2

Alarm 1 Time
Delay

From 1 to 60 seconds in 1
second intervals

Alarm 2 Time
Delay

From 1 to 60 seconds in 0.1
second intervals

Measured Values
Measured values are speed measurements
used to monitor a machine. The 3500/50M
Tachometer Module returns the following
measured values:± 20 rpm/min

Transducer Conditioning

Auto Threshold

Alarm 2 setpoints can be set
for any two of the values
measured by theTachometer.
Alarm setpoints are set using
software configuration.

Minimum input frequency forproximity transducers is0.0167 Hz (1 rpm for 1 event
per revolution).

RPM Accuracy

User selectable from 0.2 to2.5 volts

Use for any input above
0.0167 Hz(1 rpm for 1 event/revolution)
Minimum signal amplitude
for triggering is 1 volt peakto-peak.
User selectable from +9.5
Vdc to -23.5 Vdc
Minimum signal amplitude
for triggering is 500 millivoltspeak-to-peak

4/11

Rotor Speed

Speed1
Speed Band
Peak Speed2

Rotor Speed 2

Speed1
Gap2
Speed Band
Peak Speed2

RotorAcceleration

Rotor Acceleration1
SpeedPeak Speed2

3500/50M Tachometer Module
Datasheet

Rotor
Acceleration 2

Rotor Acceleration1
Gap2
Speed
Peak Speed2

Zero Speed

Zero Speed1
Speed
Peak Speed2

Zero Speed 2

ReverseRotation

141538 Rev. T

PhysicalMonitor Module (Main Board)

Zero Speed1
Gap2

Dimensions(Height x Width xDepth)

241.3 mm x 24.4 mm x241.8 mm
(9.50 in x 0.96 in x 9.52 in)Weight0.82 kg (1.8 lb)

I/O Modules (non-barrier)

Speed
Peak Speed2
Reverse Speed1
Reverse Peak Speed
Speed (forward)
Gap2
Num Reverse Rotations

Dimensions(Height x Width xDepth)

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

Weight0.20 kg (0.44 lb)

I/O Modules (internal barrier)

1 The primary value for the channel.

This value can be included incontiguous registers in theCommunications Gateway Module.

Dimensions(Height x Width xDepth)

241.3 mm x 24.4 mm x
163.1 mm
(9.50 in x 0.96 in x 6.42 in)Weight0.46 kg (1.01 lb)

Rack Space Requirements

2 This measured value is for display

and setup purposes only. No alarms
are provided.

5/11Monitor
Module1 full-height front slot

I/O Modules

1 full-height rear slot

3500/50M Tachometer Module
Datasheet141538 Rev. T

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 to
bntechsupport.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.

cNRTLus
When used with I/Omodule ordering
options without
internal barriers

EMC
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

When used with I/Omodule ordering
options withinternal barriersElectrical Safety
European Community Directive:

Standards:
EN 61010-1

RoHS
European Community Directive:
RoHS Directive 2011/65/EUMaritime
DNV GL rules for classification – Ships,offshore units, and high speed and lightcraft
ABS Rules for Condition of Classification,Part 1l

Class I, Zone 2: AEx/Ex nA nC ic[ia Ga] IIC T4 Gc;
Class I, Zone 2: AEx/Ex ec nC ic [iaGa] IIC T4 Gc;
Class I, Division 2, Groups A, B, C,and D (W/ IS Output for Division1)
T4 @ Ta= -20˚C to +65˚C (-4˚F to+149˚F)
When installed per drawing
138547.

LV Directive 2014/35/EUl

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;

Steel Vessels Rules
Offshore Units and Structures

6/11

3500/50M Tachometer Module
Datasheet141538 Rev. T

ATEX/IECEx
When used with I/Omodule ordering
options without
internal barriers

II 3 GEx 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.

When used with I/Omodule ordering
options withinternal barriers

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.

7/11

3500/50M Tachometer Module
Datasheet141538 Rev. T

Ordering Information

Ordering Considerations

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

To add the 3500/50M Tachometer Module to an
existing 3500 Monitoring System, you musthave the following versions of firmware andsoftware:
Firmware and Software

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

Version3500/22M ModuleFirmware

Revision (1.70)

3500/01 Configuration
SoftwareVersion 4.20 orlater

3500/50M Tachometer Module
3500/50-AA-BB

3500/02 Data Acquisition
SoftwareVersion 2.52 orlater

A: I/O Module Type

3500/03 Display Software

Version 1.52 or
later

3500/50M Firmware

Revision 5.30 or
later

3500/50M

Not compatible
with any versionof 3500/20lll

I/O Module with Internal Terminations

02

I/O Module with External Terminations

04

I/O Module with Internal Barriers andInternal Terminations

B: Hazardous Area Approval Option

Consider the following guidelines andrestrictions before placing an order:
l01

External Termination Blocks cannot beused with Internal Termination I/Omodules.
When ordering I/O Modules with External
Terminations, you must order External
Termination Blocks and cables
separately.
Use Bussed External Termination Blocks
with TMR I/O modules only.
Before selecting the Internal Barrier
option, see 3500 Internal Barriers productdatasheet (document 141495).

00

None

01

cNRTLus (Class 1, Division 2)

02

ATEX/IECEx/CSA (Class 1, Zone 2)External Termination (ET)BlocksPart Number

8/11

Description

125808-05

Tachometer ET BlockEuro Style connectors

128015-05

Tachometer ET Block
Terminal Strip connectors

128702-01

Recorder ET BlockEuro Style connectors

128710-01

Recorder ET Block
Terminal Strip connectors

3500/50M Tachometer Module
Datasheet141538 Rev. T

SparesCablesPart Number

3500 Tachometer Signal to ET Block Cable
135101-AAAA-BB

288062-02

3500/50M Tachometer
Module133442-01

I/O Module with Internal
Terminations

136703-01

Discrete Internal Barrier I/O
Module with Internal
Terminations

133434-01

I/O Module with ExternalTerminations

133450-01

TMR I/O Module with External
Terminations

1349383500/50M Tachometer User
Guide04425545

Grounding Wrist Strap
Single use only00580434

Connector Header
Internal Termination
8-position
Green00580436

Connector Header
Internal Termination
6-position
Green00502133

Connector Header
Internal Termination
12-position
Blue

166M2390

Connector Header
Push-in-Spring Type
(Alternative for PN
00580436)

166M2389

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

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

3500 Recorder Output to ET Block Cable
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

9/11

Description

3500/50M Tachometer Module
Datasheet141538 Rev. T

Graphs and Figures

1.
2.
3.
4.
5.
6.

Status LEDs
Buffered transducer outputs
I/O Module, Internal Terminations
I/O Module, External Terminations
I/O Module, TMR, External Terminations
I/O Module, Internal Barrier, Internal Terminations

Figure 1: Front and Rear Views of the 3500/50M Tachometer Module

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3500/50M Tachometer Module
Datasheet141538 Rev. T

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notice or obligation. Contact your Baker Hughes representative for the most current information.
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1631 Bently Parkway South, Minden, Nevada USA 89423
Phone: 1.775.782.3611 (US) or Bently.com/support
Bently.com

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