350500 Dynamic Pressure Charge
AmplifierDatasheet

Bently Nevada Machinery Condition Monitoring

145828 Rev. T

Description
The 350500 Dynamic Pressure Charge Amplifier (DPCA) is acomponent in a dynamic pressure sensing system. Thissensing system, which monitors pressure pulsations that
result from combustion instability in gas turbine engines,
consists of a charge-coupled piezoelectric pressure sensor,
low noise interconnect cable, 350500 charge amplifier, andmonitoring device.
The dynamic pressure sensor should be a high temperature
piezoelectric type that converts dynamic pressure to anoutput signal scaled in pico-coulombs per unit of pressure.
The 350500 charge amplifier design allows its use with anumber of sensors designed to monitor combustion
instability.
The interconnect cable, which connects the sensor with thecharge amplifier, is a specially designed low-noise,
environmentally robust cable. The 350500 DPCA offers twointerconnect cable options.
The 350500 charge amplifier converts the sensor charge
signal to a low impedance voltage output signal. This signal
is suitable for Bently Nevada monitors such as the 3500/64
Dynamic Pressure Monitor. The electrical interface from themonitor to the charge amplifier, which consists of –24 Vdc
power, common, and signal, is the same as that for a Bently
Nevada Proximitor. Appropriate safety barriers can be used
between the charge amplifier and the monitoring device.

350500 Dynamic Pressure Charge Amplifier
Datasheet

145828 Rev. T

Sensitivity

Specifications

100 millivolt/psi ( 1.45 Volt/bar)±2% @ 150 Hz

All Specifications are at 23 °C ± 2 °C, (73.4 °F ±3.6 °F)

DynamicRange±50 psi pk

Installation

CommonModeRejection-40 dB or better in thepassband.

OutputResistanceFrequency
Response

50 ohm typicalOrdered option: High Low(See Figure 1)

Install per Installation Drawing 145131 in a safearea or CSA\NRTL\C Class I Division 2, Group A,
B, C, or D hazardous area or Class 1 Zone 2 IIC.
Install per Drawing 146821 for Intrinsically Safe
Division 1 or Class 1 Zone 0 IIC applications.

350500 Electrical Specifications

PhysicalPower
SupplyVoltage (atthemodule)- 19.60 Vdc to – 26 Vdc when nosafety barriers are used

SupplyCurrent

14.68 mA maximum with noload11.69 mA typical with no load

-17.75 Vdc to – 26 Vdc whensafety barriers are used.

Ordered option:
13.8 pC/psi (200 pC/bar)
16 pC/psi (232 pC/bar)
1200 pC/psi (17,404 pC/bar)
12 pC/psi (174 pC/bar)
60 pC/psi (870 pC/bar)

Expected Sensor Pole-to-Pole Capacitancefor Different Input Sensitivities
Input
Sensitivity
Option inpC/psi

Nominal Pole-Pole Capacitancein picofarads

13.83201660 to 90

1200

6,300

12100

60300

OutputOrdered option:

See figures 3 and 4Weight

246 grams (8.7 oz)

Mounting

Panel mount and 35 mm DIN
rail mount options. (SeeFigures 3 and 4)

Power/Signal Three-conductor SpringLoc
Connector
terminal strip for power,
and Wiring
instrument common, andsignal output. Accepts wire
sizes of: 0.2 mm2 to 1.5 mm2 (16to 24 AWG) without ferrules,
and 0.25 mm2 to 0.75 mm2 (18to 23 AWG) with ferrules.
Recommended field wiring is athree-conductor shieldedtriad. Maximum length of 305
metre (1000 feet) between thecharge amplifier and themonitor.

SignalInput
Sensitivity

Dimensions

SensorConnector

Two-pin LEMO EXG.0B.302.HLN(mates to LEMO FGG.0B.302 orequivalent) or
Three-pin MIL Connector
MS31128-3P (mates toMS3116F8-3S or equivalent)

Environmental Limits
Operating-20 °C to +70 °C (-4 °F to +158
Temperature °F)

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Datasheet

145828 Rev. T

MS3116F8-3S (Mil spec three pinconnector)

Storage-40 °C to + 85 °C (-40 °F to +185
Temperature °F)
Operatingand Storage
Humidity

Charge AmpConnector

0% to 95% relative noncondensing

LEMO FGG.0B.302.CLAD.56 orThree-pin MIL ConnectorMS31128-3P

145536 Interconnect Cable
Specifications

Cable
200 °C maximum (392° F)
OperatingTemperature:

Unless noted otherwise all Specifications are at
23°±2°C, (73.4°F ±3.6° F)

Conductor to 70 pF/ft nominal
conductor
capacitanceThe 145536 Interconnect Cable is a double
shielded, double jacketed, low noise treated,
twisted pair cable designed specifically for use
with the 350500 DPCA.
SensorConnector

Housing Specifications
330181 Housing.

MS3106F-10SL-4S (Mil spec twopin connector) or
MS31128-3P (Mil spec three pinconnector)

See Data Sheet (document 141195) forSpecifications and Ordering Information. Thishousing is used with 3300 XL Proximitor and canalso be used for the 350500.

Charge Amp LEMO FGG.0B.302.CLAD.56 orConnector
Three-pin MIL Connector
MS31128-3P

Up to six (6) DPCAs can be mounted in panel
mount configuration and up to eight (8) in DIN
mount configuration.

Cable
150° C maximum (302° F)
OperatingTemperature
Conductor
30 pF/ft nominaltoConductor
Capacitance

145693 Interconnect Cable
Specifications
Unless noted otherwise all Specifications are at
23°±2 °C, (73.4 °F ±3.6 °F)
The 145693 Interconnect Cable is a double
shielded, double jacketed, low noise treated,
twisted pair cable designed specifically for use
with the 350500 DPCA. It can be ordered inlengths from 1 to 15 metres in 1-metre
increments.
SensorConnector

M83723/95G10207(Mil spec two pin connector)
or

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350500 Dynamic Pressure Charge Amplifier
Datasheet

145828 Rev. T

Compliance andCertifications
FCC
This device complies with part 15 of theFCC Rules. Operation is subject to thefollowing two conditions:llThis device may not cause harmfulinterference.
This device must accept anyinterference received, includinginterference that may cause
undesired operation.

RoHS
RoHS Directive 2011/65/EU

ATEX (where the applicable dashoption has been ordered)
EN 60079-0
EN 60079-7
EN 60079-11
EN 60079-15
ATEX Directive 2014/34/EU

Hazardous Area Approvals
ATEX/IECEx
350500, 350501
II 1 G Ex ia IIC T5 Ga
II 3 G Ex nA IIC T5 Gc
II 3 G Ex ec IIC T54 Gc
T5 @ Ta = -20°C to +70°C

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350500 Dynamic Pressure Charge Amplifier
Datasheet

145828 Rev. T

Ordering Information
Dynamic Pressure Charge Amplifier
350500-AA-BB-CC-DD-EE

16 pC/psi (232 pC/bar)

01

1200 pC/psi (17,404 pC/bar)

02

13.8 pC/psi (200 pC/bar)

03

12 pC/psi (174 pC/bar)04

60 pC/psi (870 pC/bar)

B: Low Pass Frequency Option (See Figure 1)00

High01Low

C:Output Sensitivity Option
00

100 mV/psi (1.45 V/bar)

D: Mounting Option
00

Panel Mount, LEMO Connector

01

35 mm DIN Mount, LEMOConnector

02

No Mounting Hardware, LEMOconnector†1 0Panel Mount, MIL Connector†1 1Din Mount, MIL Connector†1 2

No Mounting Hardware, MILConnector

No Approvals

01

CSA/NRT/L Class 1 Div 2, Groups
A,B,C,D05

Multi Agency Approvals

Interconnect Cables

A:Input Sensitivity Option
00

00

†

Ordering options 10, 11 or 12 for D limits theinput sensitivity option (ordering option A) tobe either 00 (16 pC/psi (232 pC/bar)) or 04 (60pC/psi (870 pC/bar)).
E: Approvals

5/9145536 –01

This cable is 15.24 metres long
(50 feet) and has a MS3106F10SL-4S sensor connector.

145536 –02

Identical to -01 with overmold
on the sensor side connector.

145693 – AAThis cable has a
M83723/95G10207 sensor sideconnector and can be orderedin lengths from 1 metre to 15
metre in 1-metre increments(AA order options 01 to 15)

350500 Dynamic Pressure Charge Amplifier
Datasheet

145828 Rev. T

Graphs and Figures
Typical Low Frequency Corner vs. External Capacitance (Low Pass filter option set to ‘High’)Figure 1: Low-Pass Filter option set to ‘High’. ‘External Capacitance’ is the pole-to-pole cablecapacitance plus the capacitance of the sensor
Typical Low Frequency Corner vs. External Capacitance (Low Pass filter option set to ‘Low’)

Figure 2: Low-Pass Filter option set to ‘Low’. ‘External Capacitance’ is the pole-to-pole cablecapacitance plus the capacitance of the sensor

6/9350500 Dynamic Pressure Charge Amplifier
Datasheet

145828 Rev. T(Dimensions in inches)

Figure 3: 350500 Panel Mount Option

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350500 Dynamic Pressure Charge Amplifier
Datasheet

145828 Rev. T

Figure 4: 350500 DIN Mount Option

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350500 Dynamic Pressure Charge Amplifier
Datasheet

145828 Rev. T

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1631 Bently Parkway South, Minden, Nevada USA 89423
Phone: 1.775.782.3611 or 1.800.227.5514 (US only)
Bently.com

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