PIC-SERVO SC - JEFFREY KERR - #1

Servo Motion Control I.C.

• Servo controller for D.C. motors (brush or brushless) with incremental encoder feedback

• Serial interface connects to RS232, RS485 or RS422 communications ports

• Firmware supports multi-drop RS485 network for multi-axis systems

• Position control, velocity control, trapezoidal profiling, plus Step & Direction inputs

• Path control mode supports CNC and other coordinated motion control applications

• Programmable P.I.D. control filter with

optional current, output, and error limiting

Figure 1 - PIC-SERVO SC

28-pin, 0.3" DIPor SOIC

• 32 bit position, velocity, acceleration;

16 bit P.I.D. gain values

• EEPROM configuration allows automatic start-up in stand-alone Step & Direction mode

• Single chip solution based on the PIC18F2331 series microcontroller

The primary difference between PIC-SERVO SC and previous versions of the PIC-SERVO is that the PIC-SERVO SC incorporates encoder counting within the PIC-SERVO SC chip itself, eliminating the need for the separate PIC-ENC chip. While the hardware pin-out is no longer compatible with earlier versions, most existing software applications will work with the PIC-SERVO SC without modification. In addition, the PIC-SERVO SC incorporates a host of new features:

• 2.5 MHz quadrature encoder counting rate.

• Position, velocity and acceleration can be modified on-the-fly.

• Smooth deceleration to goal points without any end-of-motion "creep" orjerk.

• Amplifier drive options include PWM & Direction, Antiphase PWM, and 3-Phase commutation. 3-Phase mode can also be used for driving two independent half-bridges.

• Optional Step & Direction inputs can be driven from stepper-style indexing systems.

• Improved limit switch options.

• Operating parameters may be saved in EEPROM for automatic servo on power-up. Please see Section 5.7 for information regarding migration from earlier versions of the PIC-SERVO.

• •• CAUTION •••

The PIC-SERVO SC motion control I.C. is not warranted as a fail-safe device, and it should not be used in life support systems or in other devices where its failure or possible erratic operation could cause property damage, bodily injury or loss oflife.

JEFFREY KERR, LLC • www.jrkerr.com

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