PA1001A Pre-Amplifier

The Motion Sensors (MSI) PA1001A series preamplifiers allow convenient interfacing with process measuring devices and digital electronics.

This series of preamplifiers/signal conditioners is available in variable reluctance (VR) and RF sensor configurations as well as a combination unit that provides user selection of either VR or RF sensor input.

Optional features include factory installed pulse scaling and field or factory installed analog output modules. The analog output module provides both current and voltage outputs proportional to RPM, flow-rate, etc.

Installation Drawing

Input Power

  • Voltage: 8 to 30 VDC
  • Current draw: 125 mA @ 24 VDC(all options equipped)
  • Reverse polarity protected

RF Sensor Input

  • Modulation carrier frequency: 25 KHz
  • Input frequency: 5 Hz to 5 KHz, user-adjustable trigger level to eliminate false pulsing
  • Carrier adjustment to allow precise tuning of carrier signal to physical environment (e.g., air gap, wall thickness)
  • Maximum air gap: 0.160" (dependent on target geometry and construction)
  • 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: 10 Hz to 10 KHz, user-adjustable trigger level to eliminate false pulsing (higher frequencies also available)
  • Trigger sensitivity: 4 mV RMS min (note: at 4 mV frequency range 10 Hz to 3 KHz)
  • Input impedance: 40K ohms (nominal)
  • Max. input signal: 60.0 V RMS
  • Max. distance from sensor to preamp: 100'

Pulse Output Options

  • All output options are user selectable
  • Open Collector
  • TTL/CMOS fanout of 5 TTL/CMOS loads
  • 0 to 10 VDC square wave
  • Square wave tied to input voltage

Temperature Range

  • Operating: -40°F to +185°F
    (-40°C to +85°C)
  • Storage: -40°F to +302°F
    (-40°C to +150°C)

Optional Features

Pulse Scaling

  • Divisions of 2, 4, 8, 16, 32, 64 or 128 (user selectable)

Analog Output Module

Current Output

  • Accuracy +/- 0.05% of full-scale & +/-200 PPM/°C
  • Available range 4-20 mA
  • Output suitable for driving, floating, or grounded loads
  • Maximum loop impedance 500 ohms
  • Response time 3 seconds for 10% to 90%

Voltage Output

  • Accuracy +/- 0.05% of full-scale & +/-200 PPM/°C
  • Available range: 0-5 VDC or 0-10 VDC, user selectable
  • Impedance: <10 ohms
  • Response time: 3 seconds for 10% to 90%


  • Unit is intended for mounting in a conduit box and comes with 2" and 2.5" center mounting holes. Enclosure is not required but recommended to protect unit from moisture, dirt, etc.
  • Optional explosion proof box available upon request
  • Enclosure requirements: GUAx16,26,36 or equivalent


  • CE compliant to EMC Directive 2004/108/EC 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"
  • Height (standard): 0.625" (NOTE: with analog output option add 1.325"; may change with different connector types)
ATEX & IECEx Certified: Custom & Standard Speed Sensors for Intrinsically Safe applications (also approved by CSA w/NRTL/C)