ADVANCEDMOTION CONTROLS  Analog Servo Drive    120A10
The 120A10 PWM servo drive is designed to drive
brush type DC motors at a high switching frequency.
A single red/green LED indicates operating status.   The
drive is fully protected against over-voltage, under
voltage, over-current, over-heating and short-circuits
across motor, ground and power leads.  Furthermore,
the drive can interface with digital controllers or be
used stand-alone and requires only a single
unregulated DC power supply.   Loop gain, current
limit, input gain and offset can be adjusted using 14
turn potentiometers.  The offset adjusting
potentiometer can also be used as an on-board input
signal for testing purposes.
See Part Numbering Information on last page of
datasheet for additional ordering options.  The
hardware installation manual for the analog drive
family is available for download at www.a-m-c.com.
Optical Isolation Between High & Low Power 
Signals 
 Four Quadrant Regenerative Operation 

 DIP Switch Selectable Modes 
Differential Input Command 
 Digital Fault Output Monitor 
 On-Board Test Potentiometer 
 Offset Adjustment Potentiometer 
 Adjustable Input Gain 
 DIP Switch Selectable Tuning 
 Drive Status LED 
 Directional Inhibit Inputs for Limit Switches 

MODES OF OPERATION 
 Current 
 Voltage 
 IR Compensation 
 Velocity  
COMMAND SOURCE 
 ±10 V Analog 
FEEDBACK SUPPORTED 
 Tachometer (±60 VDC) 
  
COMPLIANCES & AGENCY APPROVALS 
 UL 
 cUL 
 CE Class A (LVD) 
 CE Class A (EMC) 
 RoHS II

Tuning With Through-hole Components 
In general, the drive will not need to be further tuned with through-hole components. However, for applications requiring more 
precise tuning than what is offered by the potentiometers and dipswitches, the drive can be manually modified with through-hole 
resistors and capacitors as denoted in the above table. By default, the through-hole locations are not populated when the drive is 
shipped. Before attempting to add through-hole components to the board, consult the section on loop tuning in the installation 
notes on the manufacturer’s website. Some general rules of thumb to follow when adding through-hole components are: 
• A larger resistor value will increase the proportional gain, and therefore create a faster response time. 
• A larger capacitor value will increase the integration time, and therefore create a slower response time. 
Proper tuning using the through-hole components will require careful observation of the loop response on a digital oscilloscope to 
find the optimal through-hole component values for the specific application. 
IR Compensation Notes 
For applications that will use IR Compensation mode, a resistor can be added to the location named in the table above. The 
combination of the added resistor and correct dipswitch settings will configure the amplifier for IR Compensation mode. While in 
IR Compensation mode, the amplifier will adjust the duty cycle to compensate for changes in the output current. Consult the 
amplifier’s functional block diagram and the manufacturer’s website for more information. 
Tachometer Gain 
Some applications may require an increase in the gain of the tachometer input signal. This occurrence will be most common in 
designs where the tachometer input has a low voltage to RPM scaling ratio. The drive offers a through-hole location listed in the 
above table where a resistor can be added to increase the tachometer gain. Use the drive’s block diagram to determine an 
appropriate resistor value.