Open Loop Mode	The input command voltage controls the output duty cycle of the amplifier.  This mode is available on brushless amplifiers.  Equivalent to voltage mode on brush type amplifiers.
Voltage Mode	The input command voltage controls the amplifier output voltage.  This mode is available on brush type amplifiers.  Equivalent to open loop mode on brushless amplifiers.
Current Mode (Torque Mode)	The input command voltage controls the output current (torque).  The amplifier will adjust duty cycle to maintain the commanded current.  This is the suggested mode if an external controller is used which can close the velocity or position loops.
IR Compensation mode	Input command controls motor velocity.  IR compensation mode can be used to control motor speed without a velocity feedback device.  The amplifier will adjust the duty cycle to compensate for changes in output current.  While the command response is linear, accuracy during torque disturbances is not as accurate as a closed loop velocity mode.
Hall Velocity Mode	The input command voltage controls the motor velocity.  This mode uses the hall sensor frequency on a brushless motor to close the velocity loop.  Due to the low resolution of the hall sensors, this mode is not recommended at low speeds.
Encoder Velocity Mode	The input command voltage controls the motor velocity.  This mode uses the frequency of encoder pulses to close the velocity loop.  The higher resolution of encoder feedback allows for smooth motion at all speeds.
Tachometer Mode	The input command voltage controls the motor velocity.  This mode uses an analog tachometer on the motor to close the velocity loop.  Since DC tachometers have infinite resolution, speed control can be extremely accurate with a tachometer; however, they are highly susceptible to electrical noise, most notably at low speeds.
Analog Position Loop Mode (ANP Mode)	The input command voltage controls the position of the motor.  This is essentially a modified velocity mode in which an analog device (i.e. potentiometer or transducer) provides position feedback   In this mode, the motor speed is proportional to the position error.  Amplifier models with the -ANP extension have been modified for quicker response and smaller steady state error in ANP mode.

Pot Number	Purpose	Procedure
1	Loop gain adjustment for open loop, voltage, and velocity modes.   CW=increased loop gain. Shipped in CCW position.	Adjust command signal such that the motor is turning at a slow speed (100-200rpm).  Slowly turn pot 1 clockwise until the motor begins to vibrate or “hum”.  Then turn pot 1 back counter-clockwise until vibration stops, then an additional 1 to 2 turns.   Note:  If using current mode, it is recommended that you leave pot 1 in the full counter-clockwise position.
2	Current limit.   CCW=decreased current limit. Shipped in full CW position.	Determine the peak and continuous current requirements for your system.  If available, use on-board switches to set the maximum current limits and ratios.  Determine number of turns from full CCW based on this equation:   Turns=(Isyst/Imax)*12 + 1
3	Reference in gain.  Adjusts the amplifier output to command input gain of the amplifier.   CCW=decreased reference gain. Shipped in full CW position.	For velocity or voltage control, turn pot 3 full counter-clockwise.  Adjust the command input to 1V.  Turn pot 3 clockwise while monitoring motor velocity or amplifier output voltage (depending on amplifier mode.)  Turn pot 3 until the required output is achieved for a 1V command (i.e. 1V command = 200rpm motor velocity, or 1V command = 20V amplifier output.  This pot may be left in the full clockwise position if a controller is used to close the velocity or position loops.
4	Test/Offset.  Provides either an onboard test signal or an offset DC voltage to the command loop.   Shipped in the middle of potentiometer travel (7 turns from CCW).	Offset mode (Test/Offset switch to Offset position):  Provide a zero volt command signal or pull the REF+ and REF- pins to signal ground.  If the motor shaft turns, adjust pot 4 until motion stops.   Test mode (Test/Offset switch to Test position):  This mode can be used to generate an on-board command signal by turning pot 4 in either direction.  See amplifier block diagram for voltage range of test signal.

5. How do I set the peak and continuous current limits on the amplifier?

a. If available, position the Current Scaling switch to the proper position – 100% for full current capabilities of the amplifier, 50% to reduce the maximum current output by half.

b. If available, position the Continuous Current Reduction switch to the proper position – Continuous/Peak current ratio of 50% or 25%.

c. Set the position of Pot 2 (Current Limit) from the full counter-clockwise position based on the following:

Turns = (I_syst/I_max)*12 + 1

Where: I_syst=Maximum current requirements of the system

I_max =Maximum current capabilities of the amplifier (based on amplifier ratings and positions of Current Scaling and Continuous Current Reduction switches)

Note:  If peak and continuous current ratings of the motor are not a 50% ratio, (or 25% as set by Continuous Current Reduction switch,) set the current limits according to the more limiting value.

6.  How do I find the proper phasing for my motor?

a. Since different motor manufacturers may use different hall and stator winding phase combinations, it is necessary to determine which combination to use for your motor.  Below is a table listing some motor manufacturers and the proper phasing for Advanced Motion Controls amplifiers.

If the name of the motor which you are using is not listed and a phasing diagram is available, print out and use the Commutation Phasing Worksheet to determine the proper combination.

If the name of the motor which you are using is not listed and a phasing diagram is not available, connect hall sensors A, B and C to the amplifier and test all six combinations of the motor windings to determine the proper phasing.  The motor should operate smoothly in both directions.  If the motor runs slower in one direction or if you have to move the shaft to start the motor, the combination is incorrect.  The speed should be approximately the same in both directions if the combination is correct.  Motor speed can be verified by using the velocity monitor or by measuring the frequency of the hall sensors or encoder.

Note:  The combinations listed below may not work for all motors.  If this is true for your motor, use one of the other two methods listed above.  The use of Advanced Motion Controls amplifiers is NOT limited to the manufacturers listed.  If you would like to submit additions to the list, or have any questions regarding phase combinations, please contact technical support.  

7. How do I drive a brush type motor with a brushless amplifier?

a. Remove any connections from the hall sensor pins on the amplifier. Place the phase setting switch in the 60° position. Connect the motor high volt wire to “Motor B”, and motor low volt wire to “Motor A”.

8. How do I find the J1 jumper to invert the inhibit function?

a. Remove the amplifier case and look for the J1 jumper on the PCB. It is a surface mounted 0W resistor, marked with “000”. It is outlined by a white box and marked “J1” or possibly "JS1" (Similar to Figure 1). Amplifiers which have the INHIBIT/ENABLE switch do not have the J1 jumper since this switch performs the same function.

Note:  The J1 jumper does not perform this function on PWM input amplifiers.

Figure 1: J1 Jumper

9. How should I ground my amplifier/system?

a. If no isolation exists between AC power and the amplifier DC bus (i.e. transformer), do not connect the ground of the non-isolated portion of the DC bus or an non-isolated signal ground to earth ground. This may result in equipment damage or personnel injury. Since AC common is not referenced to earth ground, very high voltage potentials may exist between the DC bus ground and earth ground.

b. In most servo systems, all common grounds are tied to earth ground at a single point. Multiple connections to earth ground creates ground loops, which are highly susceptible to noise and can create current flow between different reference points. Figure 2 shows a basic system with earth ground connections.

c. To maintain a constant command reference, connect the amplifier Signal Ground to the controller Signal Ground. This should also be tied to the ground of any external power supply which will effect the operation of the controller or amplifier (i.e. separate 5V supply for encoder).

d. Grounding of shields is difficult because there are several ways to do it. The correct place to connect an electrostatic shield is at the reference potential of the circuitry inside the shield. This point will vary depending upon whether the noise source and receiver are both grounded, or whether one or the other is floating. It is important to ground the shield at only one point to ensure that ground currents do not flow through the shield. In most applications, the shield ground should not be at a different voltage with respect to the reference potential of the circuitry. If it is, this voltage can be capacitively coupled to the shielded conductor.

Figure 2: Basic Grounding Scheme. Notice that both Signal Ground and DC Ground are connected to earth ground due to the optical isolation in the amplifier and the transformer isolation from AC power.

10.  What are +Inhibit and –Inhibit?

a. Some amplifiers have directional inhibits in addition to the master inhibit.  The directional inhibits inhibit motion in one direction while allowing the amplifier to drive in the other direction.  The directional inhibits are typically connected to contact switches on the end-stops of a machine.  If movement reaches the end-of-travel, the contact switch will activate the appropriate directional inhibit and stop the motion into the end-stop.  Since the directional inhibit only inhibits motion in one direction the amplifier will still be able to pull itself away from the end-of-travel.  This configuration protects the amplifier and motor from continuing to drive into the end-stop and causing damage.

11.  How do I identify the model number and serial number of my amplifier?

a. Advanced Motion Controls uses bar code labels to identify the model number and serial number of our amplifiers.  See Know the Code for information about our bar code labels.

Troubleshooting: