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Preamplifiers Rated for Intrinsic Safety

Product Announcement from Motion Sensors, Inc.

Preamplifiers Rated for Intrinsic Safety-Image

Intrinsically Safe preamplifiers certified to CSA (with NRTL/C) and LCIE to ATEX (94/9/EC). They are available for Class I, Zone 0, IIC and II 1 G EEx ia IIC T4 or Class I, Zone 0, IIA and II 1 G EEx ia IIA T4 hazardous locations.

Features and Specifications

Input Power:

13 to 30 VDC, 35 mA @24 VDC
(Class I, Zone 0, IIC models)

7.5 to 30 VDC, 10 mA @ < 10 VDC
(Class I, Zone 0, IIA models)

Reverse polarity protected

RF Sensor Input:

Modulation carrier frequency: 20 KHz

Input frequency: 2 Hz to 5 KHz, adjustable trigger level

Carrier adjustment: to allow precise tuning of carrier signal to physical environment (e.g., air gap, wall thickness)

Max. air gap: 0.160"

Preferred coil inductance: 1.0 mH +/- 10%

Max. distance from sensor to preamp: 100'

VR Sensor Input:

Input protected, RF and band pass filtered

Input frequency: 0 to 10 KHz, adjustable trigger level

Trigger sensitivity: 10 mV RMS min. (note: at 10 mV frequency range 10 Hz to 3 KHz)

Input impedance: 40K ohms (nominal)

Max. input signal: 600 volts RMS

Max. distance from sensor to preamp: 100'

Pulse Output Options:

All output options must be factory installed

Open collector Vmos transistor, maximum OFF voltage 30 VDC; maximum ON current

TTL/CMOS (standard) fanout of 5 TTL/CMOS loads

Ambient Temperature:

ATEX: -40°C to +80°C
CSA: -20°C to +40°C


Unit is intended for mounting in a conduit box. Enclosure is not required (unless using in Class II and III locations in which must be enclosed in an approved Class II/III enclosure) but recommended to protect unit from moisture, dirt, etc.

Optional explosion proof box available upon request

Entity Parameters:

Group IIC

To barrier:
Vmax/Ui = 30 VDC, Imax/Ii = 200 mA
Ci/Ci = 0.0uF, Li/Li = 0.50 mH

To sensor:
Voc/Uo = 5.9 VDC, Isc/Io = 64 mA
Ca/Co = 1 uF, La/Li = 3.5 mH


Intrinsically safe to CSA (with NRTL/C) and LCIE to ATEX (94/9/EC).

CE compliant to EMC Directive 89/336/EEC for use in residential, commercial, light industrial and heavy industrial environments


Unconditional one (1) year warranty if used within specifications

Physical Dimensions:

Board diameter: 2.75"

Center mounting holes: 2" and 2.5