PMD: Motion Processor (MC2800 Series)

The NavigatorTM Multiple Motor Type Motion Processor (MC2800 Series) combines the ability to control both brushed/brushless servo and microstepping motors in one chipset. The user can designate which axes are brushed and which are brushless. Available in two (MC2820) and four (MC2840) axis configurations, the MC28xx consists of two components, a 132-pin processor and a 100-pin logic device. Both components are surface mount CMOS technology and powered by 5 volts. For communicating to the host microprocessor, the MC28xx offers the option of a parallel 8-bit or 16-bit interface or an asynchronous bi-directional serial port. The motion processor offloads resource intensive motion control functions from the application's host. PMD's instruction set, common to all PMD motion processors, offers flexibility and versatility to board designers and software application programmers. User-selectable profiling modes supported by the motion processor include S-curve, trapezoidal, velocity contouring and electronic gearing. The MC28xx accepts input parameters such as position, velocity and acceleration from the host and generates a corresponding trajectory. The MC28xx has a pre-programmed PID filter with feedforward velocity and acceleration that can be scaled, has a bias offset and supports a 32-bit position error.

The PID filter operates with a 150 µsec servo loop time per enabled axis for brushed/brushless and microstepping motors. The MC28xx closes the PID loop with an incremental quadrature encoder at a maximum rate of 5 megacounts per second or with a 16-bit parallel word at a maximum rate of 160 megacounts per second. Each axis supports 16-bit DAC or 10-bit, 20 kHz PWM compatible output signals. For 2 or 3-phase brushless motors, the MC2800 provides sinusoidal commutation; initialization is achieved using Hall-based sensors or with the motion processor's own algorithm. Multiple breakpoints per axis offer precise sequencing and control of events by the application program. PLC-style instructions are provided, which operate on inputs and set outputs. The instructions use Event, Activity and Signal registers. Additional signals include two limit switches (one for each direction of travel), a home indicator and a general-purpose programmable input/output bit per axis. Eight 10-bit analog (0-5 V) inputs and 256 (16-bit wide) user-defined inputs/outputs are also available. Trace capabilities provide on-the-fly data storage to an external RAM for analyzing system performance, tuning servo filters and performing maintenance and diagnostics.

Features

• Brushed/brushless servo and microstepping control in one chipset.

• Available in 2- and 4-axis versions.

• 6-step (Hall based) or sinusoidal commutation.

• Supports 2 or 3-phase brushless motors and single phase brushed motors.

• Motion profiles include S-curve, trapezoidal, velocity contouring and electronic gearing.

• Asymmetric acceleration and deceleration to custom program a trapezoidal motion profile.

• Advanced PID filter with velocity and acceleration feedforward, bias offset and 32-bit position error.

• Velocity and acceleration changes on-the-fly for trapezoidal and velocity-contouring profiles.

• Incremental encoder quadrature input and parallel input for absolute encoder or resolver.

• Parallel and serial (point-to-point or multi-drop) communications interface.

• Trace capabilities for system performance checks, servo-tuning, maintenance and diagnostics.

• Encoder rate of 5.0 Mcounts/sec allows use of fine resolution feedback devices.

• 10-bit 20 kHz PWM or 16-bit DAC motor control output to amplifier.

• 150 µsec brushed and brushless servo loop rate per enabled axis.

• Advanced breakpoint capability allows precise sequencing of events.

• PLC-style programmable inputs and outputs, including a per-axis programmable input and output.

• 256 16-bit word I/O locations for user-defined peripherals.

• 8 general-purpose 10-bit analog inputs.

• Two-directional limit switches, index input and home indicator per axis.

• Axis settled indicator and tracking window in addition to automatic motion error detection.

• Packaged in a 132-pin processor and a 100-pin logic device (surface mount CMOS technology).

• Available in commercial and industrial temperature versions.

• Software backward compatible with PMD's MC1xxx family.