Connecting to a Pittman 4400-Series Brushless Motor using MBA-6-60

Transcription

1 Application Note #5445 Connecting to a Pittman 4400-Series Brushless Motor using MBA-6-60 This application note describes the procedure for properly connecting and tuning a Pittman 4400-Series brushless DC servo motor to Galil s MBA 6-60 trapezoidal commutating drive. (!) It is strongly recommended to disconnect the load from the motor prior to power-up. In the event of a runaway, this will prevent damage to machine and personnel. A DMC-2180 is used for controlling the servo motor. A PC running WSDK was used to tune the motor. Refer to Figure (1) for a general layout. Figure (1) Basic System Layout - 1 -

2 Components referred to in this document include: Galil DMC-2180 Motion Controller CABLE-100-1M 1 meter 100-pin cable Phoenix MD/100 Optima-series breakout module MBA 6-60 trapezoidal amplifier 24V Power Supply Pittman 3-phase 4-pole brushless DC motor, model #4443S013 10BaseT Ethernet cable and Hub or Crossover Ethernet cable WSDK (Windows Servo Design Kit) PC running Windows 98SE/NT/2K/ME/XP Hardware Connections Hardware Setup Connect the DMC-2180 controller to the Phoenix MD/100 with the CABLE-100-1M cable. Make all connections to the MBA 6-60 as per Figure (2). Note that the encoder signals are single-ended. This may lead to noise issues. Use shielding where possible. For further notes on noise reduction, please see Appnote (!) When connecting the motor phases, note that the phases are labeled A, B, and C, but they do not necessarily correspond to the amplifier s actual phases. Not all signals are used at the MBA6-60. If needed, connect any other signals between the amplifier and the interconnect module

3 110VAC 10BaseT 110VAC 24V POWER SUPPLY DMC-2180 MOTION CONTROLLER +24V MOCMDX AMPENX SIG +REF IN INHIBIT 5V HALL HALL HALL1 HALL2 HALL3 MBA 6-60 AMPLIFIER PHASEA PHASEB PHASEC +24V (PUR) (BLK) (GRY) (BLU) (WHT) (RED) (ORG) (BRN) (RED)+5V (YEL)A+X (BLU)B+X (GRN)INX (BLK) ICM-1900/ ICM-2900/ PHOENIX MD/100 PITTMAN #4443S013 ENCODER: 2000 CTS/TURN Figure (2) General Connection Diagram - 3 -

4 Operation and Tuning (!) Upon power-up, it was immediately noted that the motor was in a positive feedback mode. Use MT-1 to reverse the encoder polarity. The MBA 6-60 has 4 potentiometers. The CURR LOOP GAIN and REF IN GAIN pots were placed in the center of travel. The Pittman motor was tuned by using a 500 count step signal. The motor was tuned to minimize overshoot, decrease settling time, and minimize motor hum and torque ripple. There was no load attached to the motor. The application of a load to the motor will drastically alter the tuning results. To tune the motor, the General Tuning test was used. The settings were further optimized by using the virtual oscilloscope, minimizing settling time and steady-state motor flutter. The following was a fairly typical set of values: KD 400 KP 48 KI 4 FA 3.5 Figure (3) shows the step response using the above parameters. Figure (3) WSDK Tuning Screenshot - 4 -

5 Tips and Tricks 1. Ensure that the gain potentiometers on the MBA6-60 are not at the end of travel. This allows for the DMC-2180 controller to use moderate PID gain settings. 2. If the motor appears to move well in one direction, but sluggishly in the other, or the motor stalls, or the Enable light on the MBA flickers from red to green, check the phase leads. Swap the leads until smooth motion in both directions is achieved. 3. If the motor runs away, use MT-1 to reverse feedback polarity. 4. Ensure the 24 Volt power supply can deliver enough current. If the MBA amp enable LED toggles off and on, and the motor runs extremely rough, check to see if the power supply is collapsed. 5. Minimize magnetic noise coupling by spacing the encoder and hall-effect sensors as far away as possible from the motor leads