Summary of Contents for CENTENT CN0182
- Page 1 OPERATING MANUAL CN0182 SERVO DRIVE 3879 SOUTH MAIN STREE T 714-979-6491 SANTA ANA, CALIFORNIA 92707-5710 U.S.A.
- Page 2 Centent Company product: CN0182 Servo Drive Centent and the Centent Company logo are trademarks of Centent Company. Other trademarks, tradenames, and service marks owned or registered by any other company and used in this manual are the property of their respective companies.
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Page 3: Table Of Contents
Fault Output ....................... 19 Reset Input......................20 +12 Volt Test...................... 20 Encoder Jumper ....................20 Ground........................ 20 TUNING THE CN0182 SERVO DRIVE Current Trimpot ....................21 Gain Trimpot ...................... 22 Damping Trimpot....................22 Integral Coefficient .................... 23 Servo Loop Tuning ................... 23 Interpreting Figure 12 –... -
Page 5: General Description
A light emitting diode (LED) provides visual indication of the fault condition. The CN0182 is compact, measuring 4.75" x 4" x 0.85" (121mm x 102mm x 22mm). It comes encapsulated in a heat conductive epoxy and encased in an anodized aluminum cover. This... -
Page 6: Location Of Components
(2) MOUNTING PLATE (5) MOUNTING HOLES The temperature of the drive must never be allowed to exceed 70° C (158° F). The Centent HSK heat sink kit may be ordered if additional heat sinking is required. Four mounting holes on 3.625” centers are provided to secure the drive to the heat sink or user equipment. -
Page 7: Getting Started
• Turn the CN0182 Gain Trimpot to the 9 o’clock position • Turn the CN0182 Damping Trimpot to the 11 o’clock position • Jumper the CN0182 System Inertia pins on the Option Header to Low Inertia • Connect the power supply, encoder and motor to the CN0182 Drive •... -
Page 8: Theory Of Operation
CN0182 PULSE INCREMENTAL SERVO DRIVE THEORY OF OPERATION The block diagram in Figure 2 shows the components of the CN0182 servo drive. TTL/ANALOG QUADRATURE POSITION FEEDBACK GENERATOR PROCESSOR DECODER (X4) U/D COUNTER 8 BIT D/A ANALOG SLOPE CONVERTER PROCESSOR ENCODER... -
Page 9: Auxiliary Elements
CENTENT COMPANY The PID Filter separates this signal into its proportional, integral and differential components. The proportional and differential components have adjustable gain, set by the Gain and Damping Trimpots. The integral component has a fixed gain. The trimpots control loop stability;... - Page 10 CN0182 PULSE INCREMENTAL SERVO DRIVE pulses are being sent. This results in an audible squeal and a vibration equal to one encoder count. Since a sine-cosine encoder signal contains continuous position information between encoder counts, the motor will be absolutely still when no step pulses are being sent.
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Page 11: Current Limit
Figure 5 Sine-cosine encoders usually require plus and minus power supply voltages for proper operation. The CN0182 has an on-board –5 V Generator as well as a +5 V Generator to meet the requirements of both types of encoders. If a sine-cosine encoder is used, care must be taken to accurately adjust both channels to the required ±1 volt signal amplitude in order to take advantage of interpolated accuracy. -
Page 12: Protection Circuits
CN0182 PULSE INCREMENTAL SERVO DRIVE PROTECTION CIRCUITS: The CN0182’s response to any fault condition is to turn-off the power transistors that drive the motor and turn on the Fault Led and the Fault Output Pin on the Option Header (Pin 6). - Page 13 When the oscillation amplitude reaches ±128 counts, the CN0182 will shut down. Increase the damping setting and try again. If the gain setting is to low, the drive will be sluggish in responding and an error approaching ±128 counts can develop.
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Page 14: Terminal Block Functions
CN0182 PULSE INCREMENTAL SERVO DRIVE TERMINAL BLOCK FUNCTIONS Wire of 16-22 gauge is recommended for the connections made to the CN0182. The insulation should be stripped back 0.25 inches before inserting the wire, to assure good contact with the connector. No additional terminals or connectors are required on the ends of the wire. -
Page 15: Power Supply Group
POWER SUPPLY GROUP TERMINALS 3-4 The CN0182 operates on a single voltage DC power supply, ranging between 18 VDC and 80 VDC. The power supply may be regulated or unregulated. If the power supply is regulated, it must have at least 1000 μf of capacitance on the output. -
Page 16: Encoder Group
High currents through long, light gauge wires will result in a significant voltage drop. This voltage drop can be enough to cause the CN0182 go into Under-Voltage Protect and reset. This will then cause the motor to develop a Position Error Limit and Fault Output. The result is the motor will have less performance than expected since it would have to be accelerated more slowly to avoid drawing this level of current. - Page 17 CENTENT COMPANY require substantially less power supply current to operate. Terminal 5 provides a –5 VDC power supply @ 50 mA maximum. This allows the CN0182 to interface to analog (sine-cosine) encoders. These types of encoders need bipolar (+ and -) power supplies.
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Page 18: Sine-Cosine Encoders
The CN0182 has been tested with numerous TTL and analog type encoders. Below are several encoders that have performed satisfactorily with the CN0182. This is by no means a complete list of acceptable encoders. SINE - COSINE ENCODERS... -
Page 19: Command Group
The CN0182 uses high-speed opto-isolators that can pass pulse trains up to 1 MHz. It is necessary that the Step and Direction Inputs have rise and fall times under 50 nano-seconds to avoid false steps and erratic operation. - Page 20 CN0182 and indexer is maintained. Terminal 12 is not a 5 Volt output from the CN0182. A separate, external 5-Volt supply must be connected to this terminal. Do not connect Terminal 12 to Terminal 9. A suggested hook- up for the Command Group is shown in Figure 10.
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Page 21: Option Header
CN0182 for load and motor inertia. High inertia is defined as load inertia greater than ten times the motor’s inertia. To select high inertia, jumper Pin 1 to Pin 2. To select Low Inertia jumper Pin 3 to Pin 4. -
Page 22: Position Error
In addition to being the high inertia jumper, Pin 2 also functions as the Position Error Signal. This output is used to tune the CN0182 and observe the stability of the system. The voltage on this pin ranges from 0-2.5 volts. When the motor’s position matches the command position, representing a zero position error, the voltage on Pin 2 is 1.25 volts. -
Page 23: Fault Output
The Fault LED provides a visual indication of a fault. Over-temperature, over-current and position error faults are latched faults. The Fault Output stays low; the CN0182 remains shut down. The fault state is maintained even if the condition that caused it disappears. The fault condition may only be cleared by a Reset command (Pin 7) or by recycling the power supply (power off, power on). -
Page 24: Reset Input
A reset is used to clear a fault. Releasing the Reset Input clears the fault latch and starts normal operation. The CN0182 performs a self-reset when it is powered up. The Fault LED will briefly light every time the CN0182 is powered up. -
Page 25: Tuning The Cn0182 Servo Drive
Fault Output is latched and must be reset to continue operation. See Reset Input, Pin 7. The Fault LED will light any time the CN0182 limits motor current. It will be on for the duration of current limit condition, such as a rapid acceleration or deceleration. It is a warning that a position error is developing which will lead to a Position Error Fault if further load is placed on the motor. -
Page 26: Gain Trimpot
If the system is severely under-damped, the oscillations will increase rapidly in amplitude until they exceed the Position Error Limit and the CN0182 shuts down. An over-damped system will take longer than necessary to return to the command position after a disturbance. -
Page 27: Integral Coefficient
• A 2 channel OSCILLOSCOPE with 10:1 probes • A small SCREWDRIVER Begin by connecting the power supply and the encoder to the CN0182. Do not connect the motor or pulse source yet. Jumper the Option Header for the type of encoder being used (pins 9, 10) and the expected moment of inertia. - Page 28 TTL type encoder is used. Gently try turning the motor shaft; it should resist being turned. Turn the power supply off. Connect the pulse source to the CN0182’s Step, Direction and +5 Volts DC inputs. If Function Generators are used, do the following: Set both Function Generators to the square wave setting and adjust the outputs to a ±5 volt amplitude.
- Page 29 CENTENT COMPANY Set the oscilloscope’s Channel 1 Volts/Div to .2 volts and set Channel 2 Volts/Div to 2 volts. Zero both channels to the bottom line on the display grid. Set both channels to DC Coupling. Set the Vertical Mode to display Channel 1 only. Set the time-base Sec/Div to 10 milliseconds.
- Page 30 CN0182 PULSE INCREMENTAL SERVO DRIVE Figure 12 - optimum damping Figure 13 – under-damping Figure 14 – over-damping...
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Page 31: Interpreting Figure 12 - Optimum Damping
CENTENT COMPANY INTERPRETING Figure 12 – Optimum Damping Figure 12 - optimum damping, reveals considerable detail about the motor’s dynamic response. In this example, a 1000-line encoder was used on a size 23 servo motor with no load attached. The power supply was 28 VDC and the Step generator frequency was 20.0 kHz for a motor speed of five revolutions per second. -
Page 32: Motor Fundamentals
CN0182 PULSE INCREMENTAL SERVO DRIVE × WATTS STALL MOTOR Equation 3 the terminal resistance is preferred as a means of selecting the motor instead of the stall current, use Equation 4. MOTOR TERMINAL STALL Equation 4 inally, select a motor with a no-load speed that is at least twice the maximum speed necessary to drive the load. - Page 33 CENTENT COMPANY = 13.52 OZ-IN/AMP TORQUE = 100 RPM/VOLT = I x R SPEED resistor R = TERMINAL RESISTANCE POWER SUPPLY IDEAL MOTOR LOAD motor supply resistor TORQUE RPM = K x V motor REAL MOTOR Figure 15 The ideal motor turns at 1000 RPM with a 10 VDC power supply and its speed does not change at all with load.
- Page 34 CN0182 PULSE INCREMENTAL SERVO DRIVE POWER SUPPLY = 10 VDC TERMINAL RESISTANCE = 1 OHM TORQUE CONSTANT = 13.52 OZ-IN/AMP SPEED CONSTANT = 100 RPM/VOLT 1000 RPM 10 AMPS MECHANICAL SPEED CURRENT PEAK POWER 25 WATTS SPEED CURRENT 500 RPM...
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Page 35: Specifications
CENTENT COMPANY SPECIFICATIONS UNITS ELECTRICAL Supply Voltage VOLT (DC) Current (continuous) Step Pulse Frequency Opto-isolator current Encoder Frequency Servo Lock Range -128 +128 COUNTS Signal Level TTL encoder VOLT (DC) analog encoder VOLT (DC) Supply Current +5 Volt Supply -5 Volt Supply... -
Page 36: Full Scale Drawing
CN0182 PULSE INCREMENTAL SERVO DRIVE FULL SCALE DRAWING 4.0” 101.6mm 0.7” 17.8mm 4.5” 114.3mm 3.625” 92.1mm 0.20” 5.1mm 0.186” 3.25” 4.7mm 82.6mm 1 2 3 4 5 6 7 8 9 10 11 12 0.85” 0.125” 21.5mm 3.2mm 3.625” 92.1mm...