BMC-7 CONTROLLER MANUAL

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1 BMC-7 CONTROLLER MANUAL REV L May 6, 2013 *Please check with the factory for latest version of this controller manual*

2 IMPORTANT PLEASE OBSERVE ALL MOTOR POLYGON ASSEMBLY (MPA) SPECIFICATIONS ON YOUR SPECIFIC OUTLINE AND MOUNTING DRAWING (O&M) BEFORE APPLYING POWER This controller manual describes the available features and general specifications of only the controller. The specifications on the O&M drawing for your specific MPA supersede this document. Before applying power, you must review the specifications as defined in the O&M sheet for your MPA. Failure to do this may result in damage to the MPA or the inability to meet specifications. If you do not have an O&M drawing for your motor polygon assembly (MPA), please contact Lincoln Laser Company, by phone or , to request one. You will need to provide the MPA part number along with your contact information (Name, Company, Address, Phone, and ). Check to see that the controller part number exactly matches the controller identified in the O&M Specifications sheet for the MPA. The last two digits are important. The operational accuracy WILL be met only when the correct voltage and current is available as listed in the MPA O&M specifications. Do not operate outside the RPM range specified in the O&M Specifications. Accuracy may be degraded or the MPA may be damaged. Air bearing scanners WILL be destroyed if rotated backwards. When the MPA is first powered up, check to see that the rotation (as observed from the mirror end) matches the MPA specification. Air bearing scanners WILL be destroyed if the correct orientation is not followed. Check the specification and observe the "UP arrow". Consult with the factory if you have any doubts. LINCOLN LASER COMPANY Page: ii

3 Table of Contents 1.0 Overview Specifications Operating Procedure Precautions Interface Requirements Circuit Description Output Drive: PWM: Phase Detector: Speed Reference: Speed Selection: Programmed Speeds External Speed Frequency... 9 Sync: Enable: Brake: Control Filter: Commutation: Jumper Settings JB1 Feed-Back Source: JB2 Integrator: JB3 Direction of Rotation: JB4 Two or Four Quadrant: JB5 Once per Rev: JB6 Test: JB7 Encoder divider: Connector Pin Outs: Connector Pin Orientations: Connector & Jumper Layout: Controller Dimensions Connectors & Cable Assemblies Trouble-shooting Guide Block Diagram RoHS Compliance Statement LINCOLN LASER COMPANY Page: 1

4 1.0 Overview The BMC-7 is a 3 phase, 2 or 4 quadrant closed loop brushless DC motor controller. It is designed for controlling Lincoln Laser's line of BDC motors. This controller uses a phase lock loop technique to phase-lock the motor's rotational speed to a reference frequency. The reference frequency can either be the on-board crystal reference, or the user can supply an external reference via the Input/Output (I/O) connector. If the on-board speed reference is used, 4 different factory programmed speeds can be selected via the I/O connector. The BMC-7 indicates to the user when the motor has reached the desired speed by illuminating an on board LED, and initiates a logic low output signal via the I/O connector. The BMC-7 uses a standard pulse-width modulation (PWM) scheme to provide drive current to the motor. This controller is a current mode controller. Position information is converted to a control voltage. This control voltage is used as a current command. The current is monitored as it rises through the motor winding and when its magnitude coincides with the voltage command the power drive is shut down for a predetermined amount of time and then the cycle starts over. The advantage of this scheme is for voltage bus disturbance rejection. In a standard voltage control system, voltage bus changes are corrected only after a velocity change has been seen. In a current mode control system the current is always maintained regardless of changes on the voltage bus. Either J2 or J6 is the motor connector, depending on the motor selected. Connector J2 is to be used if motor currents are expected to exceed 1.5 amps. (J2 can also be used to supply less than 1.5 amps to motor). J6 should not be used to supply more than 1.5 amps to the motor. The reason J6 is present is that it is configured to connect to LLC's line of high volume, low cost, low current MPA. *CAUTION: See section 4 when using a power supply that has overvoltage protection. LINCOLN LASER COMPANY Page: 2

5 2.0 Specifications Supply voltage... 15VDC (min) Output current (continuous)... 6 amps (J2) (peak)... 9 amps (J2) (continuous) amps (J6) (peak) 3 amps (J6) 48VDC (max) Motor pole count... All Winding requirements... 3 phase "Y" or "DELTA" configuration Minimum winding inductance millihenries required. Hall requirements... Digital hall type (120 degrees electrical spacing) Hall supply voltage... 12VDC Hall sink current capability ma Speed range to 55,000 RPM (Load Dependent) Heat sink temp deg. C. (max) Humidity range... 80% non condensing (max) Storage temp C to +75 C LINCOLN LASER COMPANY Page: 3

6 3.0 Operating Procedure Please read and understand the entire manual before attempting this procedure. 1. Connect the phase and hall leads into either J2 or J6 depending on the supplied motor. The proper pin-outs are shown in section Connect the I/O cable to the controller at J5. Refer to section 6.4 and 6.5 for speed selection criteria. Leaving MODE, LINE 1, and LINE 2 floating will command the controller to run at the default speed (speed 4 on O&M drawing). 3. With the power supply turned off, connect the power supply cable to J1. Ensure that the polarity is correct. 4. After all connections are made, turn the power supply on. 5. Apply a logic low signal (0V) to the motor enable command line (J5 pin 4). The enable line may be shorted directly to J5 pin 7 (GND). The motor should start to accelerate. 6. When the motor has reached the desired speed and phase locked, the on board LED will illuminate and J5 pin 8 will be forced to a logic low for system monitoring. 7. To turn the motor off, simply provide a logic high (5V or float) to J5 pin 4. Controller Power Connector - Use supplied cable with voltage specified on O&M drawing. Red wire is positive! J1 Index Index Ch B Ch B Ch A Ch A GND/Shield Encoder Output - Use with systems needing output. No cable supplied! J4 Encoder Input - Connect supplied encoder cable from encoder (optional). MPAs without encoders will not have a cable to this connector! Pin 1 J3 J5 Figure 1 J2 Pin 1 J6 Motor Connectors - Use connector on MPA or supplied motor cable. Only use one connector! IO Connector - Use supplied cable to control inputs and monitor outputs. Enable must be pulled low for motor to spin! Ext. Freq. Input GND Mode Input Enable Input Line 1 Input Line 2 Input Output Ext. Feedback Input 1/Rev Output LINCOLN LASER COMPANY Page: 4

7 4.0 Precautions As with any electronic circuit, normal ESD precautions should be observed. Do not change direction of rotation while motor is rotating. Back EMF currents produced by the rotating motor could damage the motor output drives. It is recommended that the motor controller be powered by a separate power supply. This will ensure that motor noise and ground bounce effects are isolated from the user system. It is important to eliminate multiple ground paths and /or ground loops. The ground pins supplied on J5 shall be used as the common ground point between the controller and the user system. Any I/O interface on the user system must use this ground to ensure proper function (see fig 2). Do not use any signals on the motor connectors J2 and/or J6 for anything other than interfacing to a motor. Do not use a power supply that uses a crowbar over-voltage protection scheme. During motor disabling, the back-emf of the motor is stacked on the power supply voltage for a short instant of time that will cause the power supply to clamp its output to ground. This will allow unregulated motor currents to be forced through the output drive transistors causing them to burn out. It is recommended that a power diode be placed in series with the positive supply lead when using switching power supplies or over-voltage protected supplies. This will eliminate the spikes at the supply that can occur from turning on and off inductive motor loads (see fig 2). Power Diode DC Motor Power Supply + - +V -V J1 J2,J6 Stator GND Hall GND BMC-7 User System IO Pins J5 Pin 2,7 GND FIG. 2 LINCOLN LASER COMPANY Page: 5

8 5.0 Interface Requirements All inputs to the I/O connector J5 have 4.7KΩ pull up resistors to +5V. It is suggested that open collector drives be used to exercise these lines from +5V to 0V (see fig. 3A). Ensure that when providing a logic low on these lines that a maximum of 0.3V is applied. If ground is used to provide a logic low, ensure that it is common to the controller ground. The maximum sink current from any single I/O line is 1.5 milliamps. External of controller J5 +5V 4.7K Internal of controller J5 +5V 4.7K Outputs Inputs Internal of controller External of controller FIG. 3A FIG. 3B All outputs from I/O connector (J5) are open collector type. It is suggested that 4.7KΩ pullup resistors to +5V be used to monitor these lines (see fig. 3B). Ensure that a common ground exists between the controller ground and the +5V supply used for pull-up resistors. Switching and linear supplies can be used to supply the BMC-7 with power. Please see section 4.0 for power supply warnings. The power supply current rating should be based on the scanner acceleration current requirements as defined on the scanner Outline and Mounting drawing. LINCOLN LASER COMPANY Page: 6

9 6.0 Circuit Description 6.1 Output Drive: The output drive consists of three half bridge outputs. Each half bridge has 2 recirculation diodes: One from source to phase and one from phase to Vbus (see fig. 4). These diodes protect the half bridge MOSFETs from back EMF during switching and pulse-width modulation decay. Vbus To Motor Phase To Current Sense FIG. 4 Power MOSFETs are used to supply current to the motor. A low value sense resistor is in series with the bottom drive power switches. The sense resistor is monitored as a voltage builds up across it. When the voltage builds up to a point dictated by the error signal, the output drives shut down for a predetermined amount of time and the cycle starts over. 6.2 PWM: A basic PWM scheme is used to deliver energy (current) to the motor. The PWM frequency is chosen based on the motor electrical time constant and is either 31 KHz or 63 KHz. The PWM duty cycle is altered by the loop filter's error signal to control the average amount of current going to the motor. 6.3 Phase Detector: The phase detector is a digital type detector that detects the rising edges of the reference frequency and the rising edge of the feedback signal. When any static frequency error exists between the inputs the output is set to either a high or low level; a high level if the feedback signal is greater in frequency, a low level if the reference signal is greater in frequency. When the frequencies are equal the output remains at the middle level of 2.5v. The resulting gain of the phase detector is 5V/4π radians or about 0.4V/radian. The dynamic range of the detector is ± 2π radians. LINCOLN LASER COMPANY Page: 7

10 6.4 Speed Reference: The BMC-7 provides an on board speed reference frequency. This reference is comprised of a 4 MHz oscillator, divide by 4, 12 bit counter, digital comparators, a 4 channel multiplexer, and a flipflop. The 12 bit counter is used to produce one half cycle of a square wave (see fig. 6). Once the counter has reached the desired count, it is reset and the count starts over. The reset signal is also used to clock a flip-flop which produces a square-wave output that is used by the system as the speed reference frequency. Since the 4 MHz oscillator is divided by 4, the resolution of the one half cycle count is 1 microsecond. Thus, the factory programmable speeds are discrete values and not all speeds can be programmed exactly. The count value is calculated with the following formula: ((Effective poles / 2) X Motor RPS) - 1 = Count value. 4 MHz Osc. Div 4 12 bit counter Digital Comp. LINE 1 LINE 2 Reset Digital Comp. Digital Comp. 4 CH Mux Reset Flip Flop Speed reference frequency output Digital Comp. FIG. 5 Count value FIG. 6 LINCOLN LASER COMPANY Page: 8

11 6.5 Speed Selection: The programmed speeds and external speed reference depend on the specific MPA and controller being used. Refer to the specific Outline and Mounting drawing that was included in your MPA shipment. Contact the factory with your MPA part number (1-2-xxxx-xxx-xx) if you need a copy of the O&M drawing Programmed Speeds Four different speeds can be programmed at the factory and can be accessed via LINE 1, LINE 2 and the MODE line on the I/O connector J5. The speeds programmed for your specific MPA are listed on page 2 of the O&M drawing. Accessing one of the four speeds is accomplished by providing the appropriate 2 digit binary code (see table 1). A 0 equals logic low (0V J5-7) and a 1 equals logic high (+5V or open). Refer to section 5.0 for the interface requirements or leave the signal open for a high and connect to J5-7 for a low. The MODE line is used to select whether the speed reference frequency is the on board reference or a user supplied speed reference (see table 2). The Mode and Line signals are internally pulled high so if no connections are made the internally programmed speed 4 will be selected. Speed 4 is the default speed. Line 1 Line 2 (J5-5) (J5-6) Speed Mode Speed Reference Source (J5-3) 0 External frequency select 1 Internal frequency select TABLE 1 TABLE External Speed Frequency The user can provide the speed reference frequency using the I/O connector J5 pin 1 and 2. The speed reference is a square wave with amplitude of +5V (J5-1) referenced to ground (J5-2). The external frequency required is dependent on the effective pole count found on page 2 of the Outline and Mounting drawing. Use the following formula to calculate the external speed reference frequency for a particular desired speed: (Effective poles/2) X (Desired RPM/60) = External Speed Reference Frequency For example, if the desired speed is 6000 RPM and the effective poles on the O&M drawing is 4, then the external frequency applied will be 200Hz. LINCOLN LASER COMPANY Page: 9

12 Sync: An at sync signal (logic low) is provided to inform the user that the motor is at speed and is phase-locked to the reference frequency. This signal is available to the user on the I/O connector J5 pin 8. An on board green LED provides a visual indication of this signal. 6.7 Enable: Enable is used to enable motor rotation. This line is on the I/O connector J5 pin 4. When the enable is deactivated (pulled high or floated) it disables the motor drive. Connect this line to J5-7 to enable the motor. 6.8 Brake: An option for controlled braking is available but must be configured by the factory. The brake is engaged when the motor is disabled meaning the Enable line (J5-4) is pulled high or floated. During braking the motor windings are shorted together when the current is below a threshold value. This protects the motor and controller while applying some gentile braking action. 6.9 Control Filter: The control filter consists of 2 parts; a low pass reference filter, and a lead/lag loop-filter (see fig. 8). FROM PHASE COMPARATOR 2.5V TO POWER DRIVE LOW PASS FILTER LEAD NETWORK FIG. 8 LINCOLN LASER COMPANY Page: 10

13 6.10 Commutation: The phase commutation is described in table 3. Hall Input JB1 Output H1 H2 H3 Positio PH A PH B PH C n High Low High B-C Z Low High High Low Low B-C High Low Z High High Low B-C High Z Low Low High Low B-C Z High Low Low High High B-C Low High Z Low Low High B-C Low Z High High Low High A-B Z High Low High Low Low A-B Low High Z High High Low A-B Low Z High Low High Low A-B Z Low High Low High High A-B High Low Z Low Low High A-B High Z Low TABLE Jumper Settings JB1 Feed-Back Source: Jumper JB1 can be used to select the source of the feedback. Feedback pulses are typically generated by the same hall-effect devices used to commutate the motor phases, an encoder (mounted to motor shaft) or a Start of Scan (SOS) detector located in the final optical system. The positions for JB1 are described in table 4. JB1 Position Name Feedback Description per Revolution A Tachometer Output is 3 (3 halls) times the motor pole count B Encoder Output is encoder CH B line count divided by JB7 setting C Start of Scan Signal from connector J5 pin 9, output is same as mirror facet # D One hall sensor Output is motor pole count divided by JB2 Integrator: TABLE 4 Jumper JB2 disables the integrator from the control loop. The integrator is functioning if jumper JB2 is not installed and C17 and R65 are installed. LINCOLN LASER COMPANY Page: 11

14 JB3 Direction of Rotation: Direction of rotation is determined by the position of jumper JB3. If using an LLC motor, clock-wise rotation is usually achieved with JB3 in position "A-B". NOTE: direction of rotation is viewed from mirror end of MPA (Motor Polygon Assembly). For counter clock-wise rotation use position "B-C". JB3 determines the motor commutation sequence (see table 3) JB4 Two or Four Quadrant: Jumper JB4 is used to select either 2 or 4 quadrant operation. With JB4 in position "A-B" 4 quadrant operation is achieved. Position "B-C" enables 2-quadrant operation JB5 Once per Rev: Jumper JB5 selects the source of the 1/rev signal. In position B-C the 1/rev signal comes from one hall sensor. This circuit will only function properly with a 4 pole motor. In position A-B the 1/rev signal comes from a special detector inside the scanner. This detector must be special ordered and is not available on every scanner JB6 Test: Jumper JB6 is used for in-factory testing and must be in the B-C position for normal operation. The controller will not function with jumper JB6 in the A-B position JB7 Encoder divider: Jumper JB7 is used to divide down the external encoder pulses to select the servo gain range when the encoder is used for feedback. Table 5 defines the divisor for each position. Position Divide by 'A' 2 'B' 4 'C' 8 'D' 16 'E' 32 'F' 64 'G' 128 'H' 256 'I' 512 'J' 1024 'K' 2048 'L' 4096 TABLE 5 LINCOLN LASER COMPANY Page: 12

15 6.12 Connector Pin Outs: Power In Connector I/O Connector J V return (Gnd) J External Freq. Input J V return (Gnd) J Gnd J V return (Gnd) J Mode J V J Enable J V J Line 1 J Line 2 J Gnd J5-8 Sync J Ext. Feedback J /Rev Output Motor Phase and Hall Connectors J Phase A J Phase A J Phase B J Gnd (phase cable shield) J Phase C J V (hall power) J Stator Gnd J Gnd J V (hall power) J Hall 2 J Hall Gnd J Phase B J Hall 3 J Phase C J V J Gnd (hall cable shield) J Hall 2 J Hall 1 J /Rev J Hall 3 J Hall 1 J Gnd Encoder In Encoder Out J V ( encoder power ) J Gnd/Shield J Gnd/Shield J ChA J ChA J ChA J ChA J ChB J ChB J ChB J ChB J Index J Index J Index J Index LINCOLN LASER COMPANY Page: 13

16 6.13 Connector Pin Orientations: J1 J4 J3 J5 J6 PIN 1 PIN 1 PIN 1 PIN 1 PIN 1 PIN 5 PIN 7 PIN 8 J2 PIN 6 PIN 1 PIN 10 PIN 10 PIN 5 PIN Connector & Jumper Layout: JB4 JB3 JB1 J2 J6 J1 JB2 JB7 JB6 J4 J3 JB5 J5 LINCOLN LASER COMPANY Page: 14

17 7.0 Controller Dimensions Note: All Dimensions in Inches LINCOLN LASER COMPANY Page: 15

18 8.0 Connectors & Cable Assemblies On-Board Connectors ITEM LLC PN MFG MFG PN MATING LLC PN MATING MFG PN CONTACT LLC PN CONTACT MFG PN J C MOLEX G V J D MOLEX Y V J T TE V N J R TE V X J B TE W NA NA J V TE Z X Cable Assemblies The following standard cables are shipped with all controllers. Please contact the factory if optional lengths are required. DESCRIPTION LENGTH END 1 END 2 LLC PN OPTIONAL Power Cable 3 feet J2 Mate Leads feet IO Cable 3 feet J7 Mate Leads and 6 feet Motor cables are included with the MPA and are generally not supplied with the controller. If you require the controller to be some distance away from the MPA please contact the factory. LINCOLN LASER COMPANY Page: 16

19 9.0 Trouble-shooting Guide Symptom Motor will not rotate Motor rotates sometimes but not always Controller pulling excessive current (from normal) Slow time to sync (from normal) Incorrect speed Motor rotates wrong direction Led flickers (bad speed stability) Possible Cause Missing main power Controller not enabled Incorrect wiring to motor Defective hall or halls Reference frequency missing Incorrect logic level on mode line Defective motor cable Defective hall Intermittent motor cable Phase short to case of motor Phase and or hall miswired to controller Excessive drag in motor (preload, bearings) Motor timing not optimized Phase short to case of motor Phase and/or hall miswired to controller Excessive drag in motor (preload, bearings) Motor timing not optimized Incorrect R-sense Incorrect reference frequency Motor pole count different than expected Feedback frequency different than expected Wrong jumper JB3 Phase and/or hall miswired Incorrect loop-filter values Unstable reference frequency Noisy reference frequency Noisy halls Excessive drag in motor LINCOLN LASER COMPANY Page: 17

20 10.0 Block Diagram Speed Ref. (Int.or Ext.) PLL Integrator Loop Filter Power Drive To Motor Feedback (Hall, Encoder, or External) Current Limit From Motor Encoder In (J3) DC Input Power Encoder Out (J4) Voltage Reg. Ext. Freq. In Speed Ref. Select Enable I/O Speed Select Sync 12V Ext. Feedback 5V 1/Rev 11.0 RoHS Compliance Statement Lincoln Laser Co. certifies to the best of its knowledge that the BMC-7 motor controller conforms to the European Union s Restriction of Hazardous Substances (RoHS) Directive 2002/95 /EC. Conformance to the RoHS Directive is achieved through the enforcement of RoHS restrictions with all of our applicable vendors and subcontractors. The table below defines the hazardous materials and their limits based on the Directive: Substance Limit (ppm) Limit (% Weight) Lead (Pb) % Mercury (Hg) % Hexavalent Chromuim (Cr +6 ) % Polybrominated Biphenyl (PBB) % Polybrominated Diphenyl Ether (PBDE) % Cadmium (Cd) % LINCOLN LASER COMPANY Page: 18

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