‘ENCORE’ SERIES SERVO AMPLIFIERS MODEL 1500 USER MANUAL ARCEE AUTOMATION NO.32, BLOCK II, SIDCO COMPLEX, GUINDY, CHENNAI 600 032.
INTRODUCTION The ‘Encore’ Series amplifiers are second generation products designed for low cost and high performance. They are designed for edgewise mounting and can operate from power supplies ranging from 24V to 150V DC. A wide range of inductive loads can be driven by the amplifiers. All models feature fully differential inputs for the control, or reference, voltage. Enable inputs for the control of outputs, and status signal and current monitor output are provided to ease system interfacing.
SALIENT FEATURES MOSFET DRIVE FOR HIGH EFFICIENCY Rugged power MOSFETs are used in the power stage. These have lower losses than comparable bipolar transistors, resulting in higher efficiency and also improved reliability due to lower temperatures. Also, MOSFETs have peak current ratings of approximately 10 times the average current, which makes them totally immune to spikes and surges.
TECHNICAL SPECIFICATIONS : MODEL ENCORE 1500 Typical specs at 25 degrees C, supply voltage = 150V DC, load = 0.25 mH + 2 ohms. SUPPLY VOLTAGE Minimum supply voltage Typical operating supply voltage Maximum operating supply voltage Typical Aux. Supply for cooling fan : : : : 24 V DC 150 V DC 155V DC 220V AC 50Hz 0.2 Amps OUTPUT POWER Peak power output @ 15A, 150V ( 2 sec unipolar / 4 sec bipolar) : Continuous power output @ 7.
ADJUSTABLE SETTINGS Trimpots : Peak current, Continuous current, Reference gain, Feedback, Tachometer gain, Balance, IR compensation. DIP switches : Load inductance, Voltage feedback, Alternate compensation, Low gain, Flat gain, IR compensation, Normal polarity. LED INDICATOR Normal / Fault LOGIC INPUTS Enable Pos Enable Neg Enable Reset - Red / Green ( Bicolour) 74HC levels, active low.
CONNECTORS : SIGNALS AND PINOUTS Motor and power connections are made via a four terminal screw connector ( P2 ). Signal connections are made via a 15 pin 0.1” pitch connector ( P1 ). 4 PIN POWER CONNECTOR P2 PIN 1 : MOTOR OUT +, positive output PIN 2 : MOTOR OUT -, negative output PIN 3 : + HV RETURN and chassis ground PIN 4 : +HV, the high voltage DC power input. 15 PIN SIGNAL CONNECTOR P1 PIN 1: +12V OUT, 10 mA MAX. PIN 2 : ENABLE-, ACTIVE LOW CMOS INPUT. PIN 3 : NEG ENABLE-, ACTIVE LOW CMOS INPUT.
operating in the velocity mode. If no tachometer is used, typically you will be operating in the current mode. In both these modes, the amplifier operates as a current source, and the difference between them is in the setup of the servo preamplifier, the section between the PWM power stage and the input differential amplifier. The amplifier can also be operated as a voltage source.
FRONT PANEL ADJUSTMENT TRIMPOTS REF. GAIN : Attenuates the output of the reference signal gain differential amplifier. Fully CW will send the full reference signal to the servo preamplifier stage. CCW rotation will result in less reference signal sent to the preamp. This adjustment acts like an overall ‘volume’ control for the amplifier, controlling the amps-out per volt-in. TACH. GAIN : Adjusts the tachometer scaling signal. When fully CW, a 10V reference signal will demand 10V from the tachometer.
DIP SWITCHES S1,S2 : LOAD INDUCTANCE SELECTOR. Set these two switches based on the inductance of the load and supply voltage. S1 S2 at 75V at 150V On Off Off On On Off 0.13 to 0.75 mH 0.8 to 5 mH 5.1 to 20 mH 0.25 to 1.5 mH 1.6 to 10 mH 10.1 to 40 mH S3 : VOLTAGE FEEDBACK. No effect when off. When on this switch substitutes the output voltage divided by 25 in place of the tachometer, converting the amplifier from a current to a voltage amplifier. If the gain of 25 is too high, use the Ref.
CONNECTING THE AMP IN CURRENT MODE ( NO TACHOMETER ) Use this checklist for applications that don’t require a tachometer. These include control systems that get their feedback from an encoder, as well as non-motor applications that require a set current from the amplifier in response to the control voltage at the input. 1. Connect DC power supply to the amplifier HV and ground. 2. Ground the amplifier chassis at P2-3. 3. Connect motor or load between OUT+(P2-1) and OUT-(P2-2). 4.
CONNECTING THE AMP IN VELOCITY MODE ( WITH TACHOMETER ) Use this checklist for applications that require velocity mode and a tachometer. 1. Connect DC power supply to the amplifier HV and ground. 2. Ground the amplifier chassis at P2-3. 3. Connect motor or load between OUT+(P2-1) and OUT-(P2-2). 4. Connect tachometer between tach input and signal ground. 5. Connect a reference voltage source between REF+ and REF- inputs. 6. Ground ENABLE, POS ENABLE and NEG ENABLE signals to logic ground. 7.
CONNECTING THE AMP IN VOLTAGE MODE Use this checklist for applications that require velocity mode but no tachometer. IR comp can be used to greatly improve the speed regulation. 1. Connect DC power supply to the amplifier HV and ground. 2. Ground the amplifier chassis at P2-3. 3. Connect motor or load between OUT+(P2-1) and OUT-(P2-2). 4. Connect a reference voltage source between REF+ and REF- inputs. 5. Ground ENABLE, POS ENABLE and NEG ENABLE signals to logic ground. 6.
POWER SUPPLY AND WIRING CONSIDERATIONS 1. Make sure that the applied supply voltage is adequate to drive the motor at maximum current and maximum RPM. This should equal the maximum motor voltage on load, plus saturation losses in the amplifier and an extra 5 to 10 percent for ripple. 2. Under low input supply conditions, the voltage requirement of (1) may not be met, and this may be seen effectively as poor regulation at high speeds, since the amplifier may not have adequate ‘headroom’. 3.
ENABLE INPUTS The enable inputs may be driven through relay contacts, NPN transistors or sensors, etc. The signals must be low ( pulled to ground ) to enable. The positive and negative enable signals can be used for selective enabling, for example in a linear system to cut off the drive at end-of-travel limits. For shutting off the entire amplifier, for example from a control system, use the Enable input.
TROUBLESHOOTING GUIDE Amplifier NORMAL light does not come on. 1. Check that at least between 24V and 150V DC is available at the amp’s DC power input. Increase or decrease supply if outside these limits. 2. Check that the enable signal is low ( active ). Amplifier FAULT light is always on. 1. Check for high temperature caused by failure of cooling fan or loss of 220V AC supply to cooling fan. 2. Check for possible short from motor wires to ground, or across motor wires.
FEEDBACK BALANCE PEAK I CONT I IR COMP TACH REF GAIN S1 S8 FLT/NORM P1-15 P1-1 OUT + OUT GND HV E NCO RE PWM SERVO AMPLIFIER
