MODELS 4122, 4212 DC BRUSH SERVO AMPLIFIERS MODEL POWER I-CONT I-PEAK FEATURES 4122 +22 to +90 VDC 10 20 4212 +22 to +125 VDC 6 12 • Only one potentiometer! • Component socket configures amp completely • Flexibility! Internal 40-pin socket configures amp with no soldering • Separate current limits: Continuous, peak, and peak- time • No integrator windup when disabled • Fault protections: Short-circuits from output to output, output to gnd Over/under voltage Over temperature Self-reset or latch-off modes FEATURES • 3kHz Bandwidth An internal solderless socket holds 17 Models 4122 and 4212 are third- • Wide load inductance range: components that configure the various generation amplifiers for dc brush 0.2-40 mH. gain and current limit settings to motors from Copley Controls Corp. Built customize the amplifiers for a wide using surface-mount technology, these • Surface mount technology range of loads and applications. amplifiers offer plug and play operation construction, lower part in a very small package. All models take Header components permit count. industry standard ±10V control signals compensation over a wide range of load as input, and operate motors in torque inductances to maximize bandwidth with APPLICATIONS mode, or velocity mode using analog different motors. brush tachometers. Individual peak and continuous current • X-Y stages Velocity loops using brush-tachometer limits allow high acceleration without feedback are used for open-loop speed • Robotics sacrificing protection against continuous controls, or in position control loops overloads. Peak current time limit is • Automated assembly requiring improved regulation at low settable to match amplifier to motor speeds. machinery thermal or commutation limits. Model 4122 operates from +22 to • Magnetic bearings All models are protected against output +90VDC unregulated power supplies, short circuits ( output to output and and outputs 10A continuous, 20A peak. output to ground ) and heatplate THE OEM ADVANTAGE overtemperature. Model 4212 operates from +22 to +125VDC power supplies, and outputs With the /Reset input open, output • Conservative design for high 6A continuous, and 12A peak. shorts or heatplate overtemperature will MTBF latch off the amplifier until power is The active logic-level of the amplifier cycled off & on, or until the /Reset input • No soldering required to Enable input is jumper selectable to is grounded. For self-reset from such GND or +5V to interface with different change header parts. conditions, wire /Reset to ground and control cards. /Pos and /Neg enable • Custom configurations the amplifier will reset every 200ms. inputs remain ground active for fail-safe available (contact factory) operation. A bicolor led speeds diagnostics during No-pots, custom headers set-up, or for fault isolation after the unit Mosfet H-bridge output stage delivers is in service. power in four-quadrants for bi- directional acceleration and deceleration of motors. Copley Controls, 20 Dan Road, Canton, MA 02021 Tel: 781-828-8090 Fax:781-828-6547 Web: http://www.copleycontrols.com Page 1 of 1 MODELS 4122, 4212 DC BRUSH SERVO AMPLIFIERS TECHNICAL SPECIFICATIONS Test conditions: 25°C ambient, Load = 200µH. in series with 1 Ω., +HV = maximum normal value MODEL 4122 4212 OUTPUT POWER Peak power ±20A @ ±80V ±12A @ ±120V Peak time 1 sec unipolar from 0A, 2 secs. after polarity reversal Continuous power ±10A @ ±80V ±6A @ ±120V OUTPUT VOLTAGE ±Vout = ±HV*(0.97) - (Ro)*(Io) Ro = 0.2 Ro = 0.1 LOAD INDUCTANCE Selectable with components on header socket: 200 µH to 40mH BANDWIDTH Current mode: 3kHz with 200µH load at maximum supply voltage, varies with load inductance and RH15, CH16 & CH17 values PWM SWITCHING FREQUENCY 25kHz REFERENCE INPUT Differential, 94K between inputs, ±20V maximum GAINS Input differential amplifier 1:1 (Volt / Volt) PWM transconductance stage Ipeak / 6V ( I peak = peak rated output current; 6V measured at Current Ref J2-9 ) LOGIC INPUTS Input voltage range 0 to +24V Logic threshold voltage ( LO to HI transition ) 2.5V ( Schmitt trigger inputs with hysteresis ) /Enable ( Internal jumper JP1 reverses logic ) LO enables amplifier, HI disables ( Default function with JP-1 on pins 2-3. For +5V enable and GND inhibit, move JP1 to pins 1-2 ) Time delay on Enable 0.9 ms after Enable true to amplifier ON, <1ms to disable /POS enable, /NEG enable Gnd enables positive or negative output currents. +5V or open inhibits (<1ms delay) ( Setting of JP-1 has no effect on ground-active level of /POS and /NEG enable inputs ) /Reset LO resets latching fault condition, ground for self-reset every 200 ms. Input resistance 10K pull-up to +5V, R-C filters to internal logic POTENTIOMETER Balance Use to set output current or rpm to zero. RH1 = 10 MΩ for Balance function, RH1 = 100kΩ for Test function LOGIC OUTPUT +Fault ( /Normal ) HI = Overtemp OR output short OR power NOT-OK, OR NOT-Enabled; LO = Operating normally AND enabled HI output voltage +5V ( 3.3kΩ pullup resistor to +5V ) +50V maximum LO output voltage <0.5V typical, 1.25V @ 250mA max, Ro = 5Ω ( mosfet on resistance ) INDICATOR (LED) Normal Green: ON = Amplifier Enabled AND Normal ( power OK, no output shorts, no overtemp ) Red = Fault ( NOT Normal, see +Fault output above ) ANALOG MONITOR OUTPUTS Current Ref ( current demand signal to pwm stage ) ±6V @ demands ±Ipeak Current Monitor ( motor or load current ) ±6V @ ±Ipeak (1kΩ, 33nF R-C filter) DC POWER OUTPUTS ±15VDC each output in series with 10kΩ PROTECTIVE FEATURES ( Note 1 ) Output short circuit (output to output, output to ground) Latches unit OFF Overtemperature Latches unit OFF at 70°C on heatplate Undervoltage shutdown @ <20V <20V Overvoltage shutdown @ >92VDC >129VDC POWER REQUIREMENTS DC power (+HV) Transformer isolated from power mains +22 to +90VDC +22 to +125VDC Watts minimum 2.5W 2.7W Watts @ Icont 25W 41W THERMAL REQUIREMENTS Storage temperature range: -30 to +85°C; operating temperature range: 0 to 70°C baseplate temperature MECHANICAL Amplifier case size 4.3 x 3.0 x 1.0 in. (109 x 76.2 x 25.4 mm.) Weight 0.43 lb (0.2 kg.) CONNECTORS 2 2 J1 (Power & motor): 5 position compression-connector; Phoenix MKDS 3; maximum wire gauge AWG 12 ( 4 mm solid or 2.5 mm stranded ) wire. J2 (Signal): 16-position 0.1” centers housing ( Molex: 22-01-3167 ) with AWG 30-22 crimp contacts ( Molex 08-50-0114 , 16 required ) NOTES 1. Latching faults disable amplifier until power is cycled off-on, or /Reset input is grounded. Non-latching faults re-enable amplifier when fault condition is removed. Overtemperature and short-circuits are latching faults, under or overvoltage faults are non-latching. If /Reset input is grounded, amplifier will auto- reset from latching faults every 200ms. Copley Controls, 20 Dan Road, Canton, MA 02021 Tel: 781-828-8090 Fax:781-828-6547 Web: http://www.copleycontrols.com Page 2 of 2 MODELS 4122, 4212 DC BRUSH SERVO AMPLIFIERS FUNCTIONAL DIAGRAM * JP1: PINS 2-3 FOR /ENABLE AT J2-11 GND PINS 1-2 FOR /INHIBIT AT J2-11 10 3 2 1 ENABLE * INTEGRATOR RESET SWITCHES 11 *JP1 RH2 100 K TURN ON WHEN AMP IS DISABLED POS ENABLE AUX 16 LED 12 INTEGRATOR GREEN = NORMAL STATUS NEG ENABLE RED = FAULT & 13 TACH LEAD CONTROL TACH (-) CH5 CH9 (OPEN) RH4 NOTE: +5V LOGIC - * 14 +FAULT OUTPUT 6 DEFAULT VALUE OF CH11 IS 0 OHMS FOR TORQUE MODE OPERATION RESET GND 15 FOR VELOCITY MODE ( BRUSH TACH ) 7 RH3 100 K CH11 RH10 MOMENTARY SWITCH CLOSURE RESETS FAULT * CH17 + REPLACE CH11 WITH 4.7NF RH15 WIRE RESET TO GROUND FOR SELF-RESET 60.4 K REF LEAD REF AMP J2 SIGNAL CONNECTOR RH6 CH8 CURRENT LIMIT Gv = 1 CH16 SECTION 100PF REF(+) 47K 4 - - VALUE DEPENDS ON MODEL - - + + SEE "ARMATURE INDUCTANCE" TABLE REF(-) 5 RH7 100 K RH12 182K + + PEAK SERVO CURRENT CURRENT J1 MOTOR & POWER CONNECTOR ERROR PREAMP 47K AMP RH13 4.7MEG CONT CURRENT MOTOR +15V CH14 0.47U PWM PEAK STAGE CW RH1 + - TIME OUTPUT MOSFET BALANCE CURRENT "H" MOTOR + 10 MEG Voltage gain = 1 50K BRIDGE SENSE 1 MOTOR - -15V 2 +/-6V for VOLTAGE GND 1K +/-Ipeak CURRENT GAIN 3 9 REF GND 4.8 kHz FILTER Gv = +HV 4 33NF 10 +HV +/-6V at 5 1K +/-Ipeak CURRENT 8 MONITOR 4.8 kHz FILTER 33NF 1K GND 2 +HV 10k CASE MAY BE GROUNDED +15 +15V +5 1 DC / DC AUXILIARY FOR SHIELDING +15 CONVERTER DC OUTPUTS 10k -15 3 -15V -15 CASE GROUND NOT CONNECTED TO CIRCUIT GROUND POWER GROUND AND SIGNAL GROUNDS ARE COMMON TYPICAL CONNECTIONS TORQUE MODE ENCODER VELOCITY MODE ENCODER REF+ + 4 1 REF+ + J1 J2 MOTOR 4 1 REF- J1 5 J2 MOTOR 2 REF- 5 2 6 J2 TACH + 7 10 GND GND 10 ENABLE 11 3 ENABLE 11 3 12 POS ENABLE J1 4 GND POS ENABLE J1 12 4 GND + NEG ENABLE 13 5 + +HV NEG ENABLE 13 5 +HV Note: JP1 on pins 2-3 ( default ) Note: JP1 on pins 2-3 ( default ) Notes 1. All amplifier grounds are common (J1-3, J1-4, J2-2, J2-7, and J2-10 ) Amplifier grounds are isolated from case & heatplate.. 2. Jumper JP1 default position is on pins 2-3 for ground active /Enable input ( J2-11 ) For /Inhibit function at J2-11 ( +5V enables ), move JP1 to pins 1-2 3. For best noise immunity, use twisted shielded pair cable for reference and tachometer inputs. Twist motor and power cables and shield to reduce radiated electrical noise from pwm outputs. Copley Controls, 20 Dan Road, Canton, MA 02021 Tel: 781-828-8090 Fax:781-828-6547 Web: http://www.copleycontrols.com Page 3 of 3 MODELS 4122, 4212 DC BRUSH SERVO AMPLIFIERS CONNECTORS AND PINOUTS J1: MOTOR & POWER CONNECTIONS Pin Signal Remarks 1 Motor (+) Amplifier output to motor (+) winding 2 Motor (-) Amplifier output to motor (-) winding 3 GND Power supply return. Connect to system ground at this pin. 4 GND Power supply return. Connect to system ground at this pin. 5 +HV +HV DC power supply input J2: AMPLIFIER BOARD CONNECTIONS Pin Signal Remarks 1 +15V +15V in series with 10kΩ 2 Gnd Signal ground 3 -15V -15V in series with 10kΩ 4 Ref (+) Differential input positive terminal for Reference voltage 5 Ref (-) Differential input negative terminal for Reference voltage 6 Tach (-) Negative terminal of brush tachometer 7 Gnd / Tach (+) Signal ground, or positive terminal of brush tachometer 8 Curr Mon Output current monitor: ±6V output at ±peak output current 9 Curr Ref Current demand signal to PWM stage: ±6V demands ±peak current 10 Gnd Signal ground 11 /Enable Amplifier enable input: enables or inhibits PWM switching at outputs Default: Gnd enables amplifier, open or +5V inhibits ( JP1 @ 2-3 ) For controllers that output +5V to enable amplifier, move internal jumper JP1 to pins 1-2 ( Gnd will inhibit, +5V or open will enable ) 12 /Pos Enab Gnd to enable output current in one polarity, open or +5V to inhibit Typically used with grounded, normally closed limit switches. 13 /Neg Enab Gnd to enable output current in opposite polarity, open or +5V to inhibit. Typically used with grounded, normally closed limit switches. 14 /Normal Current-sinking when amplifier enabled and operating normally. Goes to +5V when amplifier disabled or fault condition exists. 15 /Reset Ground to reset overtemp or output short circuit latching faults. For automatic reset of faults every 200mS, ground permanently. 16 Aux Single-ended auxiliary input. BALANCE POTENTIOMETER Default position: centered. Functions to bring output current ( in torque mode ) or output velocity ( in tachometer mode ) to zero with reference input voltage at zero, or control system output at zero. Normal range is ±1% of full scale with 10Meg resistor in header location RH1. To use the pot as a wide range set-point adjustment, install a 150kΩ resistor at RH1. Now, full CW or CCW will have the effect of a ±10V signal at the reference inputs. STATUS LED Dual color, red/green. Color +HV /Enable Short Overtemp Green Normal Active None Normal Red Too low or too high X X X X Inhibited X X X X Output short X X X X Too hot Note 1, 5 2, 5 3, 5 4, 5 Notes: 1. +HV normal >20V and <92V for model 4122, >20V and <129V for model 4212 2. /Enable is ground-active for JP1 on pins 2-3 ( default ). To reverse function, switch JP1 to pins 1-2. 3. Shorts detected by overcurrent circuit are between outputs, or from outputs to ground. 4. Overtemperature faults occur when heatplate temperature is >70°C 5. +HV and /Enable cause momentary amplifier shutdown, operation is restored when +HV is within normal limits and /Enable input is active. Output shorts, and overtemperature faults latch-off amplifier. Thus amplifier will remain off until power is cycled on/off, or /Reset input is grounded momentarily. If /Reset input is wired to ground, output short and overtemperature faults will self-reset every 200ms. Copley Controls, 20 Dan Road, Canton, MA 02021 Tel: 781-828-8090 Fax:781-828-6547 Web: http://www.copleycontrols.com Page 4 of 4 MODELS 4122, 4212 DC BRUSH SERVO AMPLIFIERS COMPONENT HEADER NO PARTS INSTALLED IN THESE LOCATIONS CH17 LOAD INDUCTANCE COMPENSATION CH16 (SEE CHART FOR VALUES) RH15 CH14 0.47UF PEAK TIME LIMIT RH13 CONTINUOUS CURRENT LIMIT 4.7 MEG 182K RH12 PEAK CURRENT LIMIT CH11 (O OHM) PREAMP DC GAIN & INTEGRATOR 60.4K RH10 CH9 PREAMP HI-FREQUENCY ROLL-OFF (SEL) (SEL) CH8 REF INPUT LEAD CAPACITOR JP1 RH7 REFERENCE INPUT SCALING 100K 3 2 1 (SEL) RH6 REF INPUT LEAD RESISTOR (SEL) CH5 J1 TACH INPUT LEAD NETWORK J2 (SEL) RH4 5 1 16 1 RH3 100K TACH INPUT SCALING 100K RH2 AUX INPUT COMPONENTS LABELLED "SEL" 10MEG RH1 BALANCE RANGE ARE NOT INSTALLED AT FACTORY USER SHOULD SELECT VALUES AS REQUIRED ARMATURE INDUCTANCE Model 4122 4212 Load (mH) RH 15 CH17 CH16 RH15 CH17 CH16 0.2 to 0.5 80.6k 2.2 nF 390 pF 69.8 k 2.2 nF 390 pF 0.6 to 1.7 200k 680 pF 220 pF 100 k 1 nF 330 pF 1.8 to 4.8 402k 680 pF 180 pF 301 k 470 pF 100 pF 5 to 14 806k 680 pF 150 pF 698 k 330 pF 82 pF 15 to 45 1.5M 470 pF 100 pF 1.21M 220 pF 82 pF Note: Values in bold & italics are factory installed standard. Values shown are for 90V (4122 ) and 125V (4122). At lower supply voltages RH15 may be increased and CH17 decreased. PEAK CURRENT LIMIT (AMP) CONTINUOUS CURRENT LIMIT (AMP) 4122 4212 RH12 (Ω) 4122 4212 RH13 (Ω) 20 12 182k 10 6 4.7Meg 16.7 10 56k 7.4 4.4 7.15Meg 13.3 8 30k 5.7 3.4 10Meg 10 6 18k 6.7 4 9.1k 3.3 2 3.9k Notes on Current Limits: PEAK CURRENT TIME-LIMIT (SEC) 1. Values in bold & italics are factory installed standard. Tpeak CH14 (μF) 2. Peak times double after polarity reversal. 1 0.47 3. Peak current limit should be set greater than continuous current limit. 0.8 0.33 If Ipeak < Icont then peak overrides continuous limit and Icont = Ipeak. Minimum setting for peak current is 0% of peak rating. 0.5 0.22 4. Continuous current sense is for average current. Symmetrical waveforms with zero 0.3 0.15 average value may cause overtemperature shutdown of amplifier or motor damage 0.2 0.10 2 due to high I R losses. 0.1 .047 5. Times shown are for 100% step from 0A with default value of RH13 ( 4.7 Meg ). When changing RH13, peak times will change. Set RH13 for continuous current limit first, then pick CH14 based on waveforms at Curr Ref ( J2-9 ). Copley Controls, 20 Dan Road, Canton, MA 02021 Tel: 781-828-8090 Fax:781-828-6547 Web: http://www.copleycontrols.com Page 5 of 5 MODELS 4122, 4212 DC BRUSH SERVO AMPLIFIERS system ground. If this voltage is added to the output of the control APPLICATION INFORMATION system, it can produce oscillation, or inconsistent operation. To IMPORTANT! ALWAYS REMOVE POWER WHEN CHANGING eliminate this effect, you should always use both reference HEADER PARTS!! inputs. Connect the Ref(+) input to the output of the controller card, and the Ref(-) input to ground at the control card. Now, the differential OPERATING MODES amplifier will measure the control signal at the control card and These amplifiers operate as either open-loop current sources, or will reject any noise that exists between amplifier and control feedback devices using analog tachometers. system grounds. As open-loop current sources, the ±10V at the reference inputs THE SERVO PREAMPLIFIER produce current in the load, typically a motor. The motor acts as a transducer, and converts current into torque, the twisting force This section processes the reference signal and any feedback at the motor shaft. This is called torque mode. It is used most signals, and generates an internal current reference signal that frequently in systems that have controllers taking feedback from controls the PWM stage to produce output currents. It is here that an encoder on the motor shaft. The computer calculates both the reference signal and tachometer signals are compared, and position and velocity from the encoder signal, processes them in the difference signal produced and amplified. a digital filter, and outputs a signal to the motor causing it to Three components on the header control the behavior of the accelerate or decelerate. servo preamp. The chart below lists the default torque-mode and As a feedback amplifier, a signal is generated by an analog brush starting-point values for velocity mode operation: tachometer mounted on the motor. This is a generator that produces an analog signal that has a polarity and amplitude Part Torque Velocity proportional to the motor speed. The amplifier subtracts the tach CH9 out 220pF signal from the reference signal, and amplifies the difference RH10 60.4k 680k between them. This is called velocity mode, because the CH11 short 4.7nF amplifier changes the motor current ( torque ) so that the motor velocity is proportional to the reference signal. CH9 controls the high-frequency roll-off. RH10 controls the loop gain, and thus the step-response TORQUE MODE OPERATION of the amplifier. CH11 ( along with RH7 ) forms the integrator that gives the Torque mode is the default configuration. For input voltages of stiffness at a standstill, or speed regulation while running. ±10V, the amplifier will output its peak rated current. In torque mode, motor current is held constant, and motor speed, CURRENT LIMITING or velocity changes as the load changes. In torque mode the gain of the servo preamplifier is simply 0.6 This stage takes the output of the servo preamplifier, and and scales the ±10V from the reference signal down to the ±6V processes it before sending it to the PWM stage. The amplitude that drives the PWM stage. of the signal is first clamped to produce peak current limiting. This The servo preamplifier integrator function is disabled, and the low signal then goes to the continuous current-limit circuit where gain is constant over a wide range of frequencies. Thus we these functions are produced. Finally, the current-limited signal is sometimes call this flat-gain mode. outputted to the PWM stage as the current-reference signal. This signal is quite useful in that the current limit action can be seen VELOCITY MODE OPERATION here and measured without connecting a motor, thus protecting it from overload during initial setup. The difference between the reference and tachometer signals is amplified and used to change the torque on the motor. Ideally, PWM STAGE the difference between the command and feedback signals would be zero, so in velocity mode operation the servo preamplifier The voltage at the output of the current limit stage is called the must have much higher gain than when in torque mode. current reference. This signal becomes the demand signal that In addition, the gain must change over a range of frequencies. controls the PWM stage. Here the current demand is converted For “stiffness” that corrects for steady-state changes, the into a current in the motor. This current can be measured at the amplifier uses an integrator. For fast response the loop gain of current monitor, which shows the response of the motor to the the servo preamplifier must be tailored to the characteristics of current demand signal. By operating as a current source, the the motor and tachometer. To control oscillations from the PWM stage is able to achieve faster response from the motor tachometer, the gain of the preamplifier must roll-off, or decrease than if was acting only as a variable voltage. at higher frequencies. The current error amplifier compares the current reference with In velocity mode, motor speed is held constant, while motor the current monitor, and adjusts the output voltage such that the current changes in response to changes in the load. demanded current flows in the motor. The gain of this amplifier is controlled by RH15, CH16, and CH17, which are used to THE PARTS OF THE AMPLIFIER compensate the amplifier for the motors’ inductance. DIFFERENTIAL AMPLIFIER The reference signal ( the command signal from the control system ) is sensed by a differential amplifier. This acts like a voltmeter with two probes, measuring a voltage between two points. Current flowing in the amplifier power wiring causes voltage drops in the wires resistance. This in turn can produce a voltage at the amplifier ground that is different than the control Copley Controls, 20 Dan Road, Canton, MA 02021 Tel: 781-828-8090 Fax:781-828-6547 Web: http://www.copleycontrols.com Page 6 of 6 MODELS 4122, 4212 DC BRUSH SERVO AMPLIFIERS INSTALLING THE AMPLIFIER TORQUE MODE SETUP Select the header components for current limits first as this will 1) Select RH12, RH13, and CH14 for motor current-limits. protect the motor during later procedures. Using the Current Ref 2) Select RH15, CH16, and CH17 on header for armature signal will allow you to view the effect of component changes on inductance. the current demand signal without loading the motor until the 3) Ground /Enable, /Pos Enable, and /Neg Enable inputs to adjustments are complete. The effects of the current limits can J2-10. ( Assumes default setting of JP-1 to pins 2-3 ) best be seen by inputting a reference signal of ±10V as a square 4) Connect amplifier to transformer-isolated DC power supply. wave of about 1/4 Hz. This way there will be enough time at 5) Adjust value of RH10 if necessary to change peaks to observe the peak time ( which will twice the unipolar transconductance. time after reversals ) and to see the continuous current value VELOCITY MODE SETUP after the peak time occurs. Begin with the default components in positions RH10 & CH11. PEAK CURRENT LIMIT This will give a lower loop gain, and the integrator will be Amplifiers are shipped with 182kΩ installed in RH12. This disabled. After loop gain has been adjusted as described below, delivers the amplifiers peak rated current. For lower settings use the integrator is setup for best stiffness and response. values from the table. 1) With the default components in RH10 & CH11, perform CONTINUOUS CURRENT LIMIT torque mode setup steps 1,2,3, and 4. This will prepare the amplifier to drive the motor within its current limits and Choose RH13 based on the motor manufacturers specification compensate the PWM stage for motor inductance. for your motor. Table values give basic settings. This setting 2) From the motor/tachometer datasheet, find the tachometer keeps the motor within its thermal limits. Note that this limit gradient. Typically this will be 3 or 7 volts per krpm ( volts per measures average current and will not work on symmetrical thousand revolutions per minute ). Multiply this number by the waveforms such as might occur during system oscillation. Use an maximum speed ( in krpm ) that you want to achieve at the external thermal circuit breaker for protection from such ±10V reference input. For example, suppose that you have a overcurrent faults. 7 v/krpm tachometer and want to operate at 3000 rpm ( 3 PEAK-TIME LIMIT krpm ) at ±10V input. Multiply the 7 v/krpm by 3 krpm to get 21V. Divide this number by your reference voltage ( 10V in Header component CH14 controls the length of time for which the this case ) and get 2.1. Now multiply the value of the amplifier will output peak current. When peak currents that are reference input resistor, RH7 by this number. Use the default less than the amplifiers peak rated current, this time will increase, value of 100k times 2.1 to get 210kΩ. A close production eventually becoming infinite as you reach the continuous current. value resistor would be 220kΩ. Install this at location RH3 to After a polarity reversal, the peak time will be twice that of a scale the tachometer input. unipolar current change. 3) Connect the motor to the Motor (+) and (-) output of the amplifier at J1-1, and J1-2. With the motor disconnected from GROUNDING & POWER SUPPLIES the load, connect up the tachometer to the tach inputs at J2-6 Connect positive terminal of power supply to J1-5, negative & J2-7. Turn on the amplifier and spin the motor gently. If it terminal to J1-4. For best results do not ground power supply, but runs away at high speed, turn off the amplifier and reverse ground each amplifier with heavy wire from J1-3 to equipment the connections to the tachometer only. Power up again and ‘star’ ground point. the loop should now be stable and motionless ( save for a If power supply is >1m. from amplifiers, add local filter capacitor small balance adjustment ) at 0 reference input. near amplifiers (250μF minimum per amplifier). 4) Apply a small step input voltage to the reference inputs. A 2V peak-to-peak square wave of 2Hz is a good start. Observe /ENABLE INPUT the signal at the tachometer input ( J2-6 ). If the signal With internal jumper JP-1 on pins 2-3 ( default position ), the overshoots and undershoots for more than one cycle, then /Enable input ( J2-11 ) must be grounded for the amplifier to reduce the value of RH10 by 30-50% and try again. If the operate. For operation with cards that output +5V to enable the response is slow without any overshoot, increase RH10 by amplifier, move the jumper on JP-1 to pins 1-2. This will reverse the same amount and re-try. Optimal gain will show a fast the /Enable input active level so that grounding the input will response with no overshoot, or a small amount that settles inhibit the amplifier, and +5V (or open) will enable. back without appreciable undershoot. If there is tachometer Note: There is a 0.9ms delay /between Enable TRUE and resonance ( high pitched squealing ) after this adjustment, amplifier ON. install a 330 pF capacitor at CH9 and increase value in steps of 3X until oscillation disappears. Re-test step response. /POS & /NEG ENABLE INPUTS 5) Install a 10 nF capacitor at CH11. Test again with square wave input, or gently twist shaft with no input. Best choice of These inputs are always ground active, open circuit or +5V will CH11 will give good stiffness at the motor shaft when tested inhibit. In service these would be grounded through normally- by turning, and will show some overshoot ( perhaps 10% ) to closed limit switches. When a motion axis enters the limit, torque a step input without ringing. As CH11 is decreased, stiffness will be inhibited to prevent further travel into the limit, but torque will increase but overshoot will increase, too. If too small, will be available to back-out of the limit switch. Because torque is CH11 will produce violent oscillation. Disable amplifier still available in one direction, the Normal led stays ON, and the immediately and change to a larger value. Normal output signal remains true. Delay on /Pos and /Neg enables is <1ms. Copley Controls, 20 Dan Road, Canton, MA 02021 Tel: 781-828-8090 Fax:781-828-6547 Web: http://www.copleycontrols.com Page 7 of 7 MODELS 4122, 4212 DC BRUSH SERVO AMPLIFIERS OUTLINE DIMENSIONS Dimensions in inches (mm.) 0.56 2.00 4.00 3.00 1.00 0.625 0.16 4.30 ORDERING GUIDE Model 4122 20A peak, 10A continuous, +22 to +90VDC brush motor amplifier Model 4212 12A peak, 6A continuous, +22 to 125VDC brush motor amplifier Copley Controls, 20 Dan Road, Canton, MA 02021, USA Tel: 781-828-8090 Fax: 781-828-6547 Web: http://www.copleycontrols.com Rev B,06/08/2010