The LDU-S1 is a low power brushed linear servo amplifier in a Eurocard 3U form factor. It is ideally suited to "stand alone" torque or velocity control applications or for position control if used with a motion controller and position feedback device. When configured for torque control, the amplifier operates as a voltage controlled current source. When configured for velocity control, the amplifier operates as a voltage controlled voltage source. If configured for velocity control, the amplifier can be further configured to accept a tachometer feedback signal for improved motor response, low speed smoothness and velocity accuracy.

The LDU-S1 has simple potentiometer adjustments for Signal Gain, Tachometer Gain, System Response, Balance, and Current Limit and a plug in Personality Component Carrier to allow customized component changes for the peak current and loop compensation parameters. The unit includes an Amp Enable input and enabled indicator LED. The amplifier also has over current limiting and RMS current shutdown circuitry. The LDU-S1 has numerous advantages over PWM type amplifiers including minimum motor heating, increased brush life and the ability to drive zero inductance loads.


  • Eurocard 3U Form Factor
  • Torque/Velocity Mode Jumper Selected
  • Can Accept Tachometer Input in Velocity Mode
  • Over Current Bus Protection
  • RMS Current Shutdown with Amp Fault Output and Indicator LEDs
  • Amp Fault Reset Switch and Reset Input
  • Amp Enable Input and Indicator LED
  • Travel Limit Inputs
  • Drives Zero or Low Inductance Loads
  • Can be Powered from Uni-polar or Bi-polar Bus Supply alone
  • Bus Voltage: 20 - 40 VDC
  • Continuous Current: 2 or 5 Amperes
  • Excellent for use with Precision Positioning Systems
  • Designed for Brushed DC Motors
  • Advanced Design, high Quality and High Reliability at a Lower Cost
  • One Year Parts and Labor Warranty


Standard Models: 4/5 4/15
Bus Voltage 20 to 40  VDC 20 to 40 VDC
Peak Output Current* 5 A for 0.5 Sec 15 A for 0.5 Sec
Continuous Output Current* 2 A 5 A
Command Input Voltage 0 to 10V 0 to 10V
Tachometer Input Voltage 0 to 40V 0 to 40V
Command Input Impedance 20 kOhm 20 kOhm
Tachometer Input Resistance 20 kOhm 20 kOhm
Minimum Load Inductance 0 H 0 H
Torque Gain 0.5 A/V 1.5 A/V
Bandwidth 20 kHz 20 kHz
Weight Narrow: 0.48 Lb (220 g)
Standard: 0.91Lb (410 g)
Recommended Chassis CHU-S3, CHU-S6 Eurocard
Available Accessories ACC-V1A Standard Backplane, ACC-V1B Narrow
Backplane, PCU-S1 Rack Mount Power Supply, ACC-V3A PMAC Interface Board

*All ratings with forced air cooling to maintain 40C heat sink temperature. Failure to keep constant air flow to the heat sink will reduce the output current capacity and may result in damage to the unit.

Ordering Information

Product Order Number
LDU-S1-4/5 Amp 1.2" 40 VDC/5A Peak WS-002-0004
LDU-S1-4/15 Amp 40 VDC/15A Peak WS-002-0012
ACC-V1A Standard Backplane WS-011-0003
ACC-V1B Narrow (1.2") Backplane WS-011-0005

 Click here to download this data sheet.

All data sheets are in Adobe Acrobat format.