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The MotionC family of boards are used to provide a stand-alone, motor control board for a number of different motion control applications.

They are expansion boards driven by a family of TERN C/C++ programmable controllers, and have flexible outputs for interfacing to a wide range of different motors.

The DSP-based solution provided by the MotionC family of products makes developing a wide range of multi-axis motion-control applications far easier.

There are three distinct MotionC boards (the base MotionC, the MotionC-P, and the MotionC-S), all described here. They are low-cost, high-performance, industrial motor controllers for up to 4-axis motion control.

Driven by a C or C++ programmable Engine controller (including the i386-Engine (IE), 40 MHz A-Engine (AE) , 586-Engine (5E), A-Engine-86 (AE86), or 80 MHz R-Engine), the MotionC is a complete, ready to run, motion controller with built in sophisticated field proven control firmware.

The Engine controller serves as the host computer and interfaces to the DSP motion control chipset from PMD (Performance Motion Devices’) via high-speed data bus. The DSP’s various interface lines are brought out to convenient pin-headers.

The user only needs to define parameters for PID algorithm and trajectory profile through the Engine. The DSP then calculates velocity, position and stabilizes the motor output. With an external interrupt line, the DSP can interrupt your running application at any time.

motion2The Motion-C provides protected inputs (Darlington transistor arrays) to optically isolate home, limit, and fault switches. The solenoid drivers on the MC are capable of sinking up to 350 mA at 50 V. The PPI (82C55) provides an additional 24 user-programmable bi-directional I/O lines.

The MC provides two RS-232 and one RS-485 drivers for the host Engine controller. Additional I/Os, ADC, and DAC are optionally available on the Engine boards.

The MC2140 supports up to 4-axis closed-loop digital servo control for a variety of brushed DC servo motors. It uses incremental quadrature encoders for position feedback. It is capable of prividing either four 12-bit DAC outputs at +-10V for motor control, or driving a motor amplifier through pulse-width modulated output.

Each axis contains sophisticated trajectory profile and digital servo capabilities, allowing very low position and velocity tracking errors. The 4-axis operation can be programmed either independently or in synchrony to allow advanced multi-axis motion such as circular and continuous-path profiles.

The DAC provides electronic gearing, PID/PI control, a choice of velocity profiles, 1/T counter, motor error shutdown and monitoring travel switches.

The MC2140 also supports a 16-bit parallel-word input mechniasm, such as ADC. Expansion headers are available for 8 channels of 10-bit ADC inputs, PWM output and trace memory expansion. The MC2120 is a 2-axis version of this controller.

The MC2520/2540 are 2/4-axis open-loop stepper versions; the quadrature decoders are still available to the user application for gauging motion.


The MotionC is also available in a -P version. The MotionC-P comes with two PPIs. 24 of these I/O remain general purpose programmable TTL-level I/O as in the case of the base MotionC; the others are used to drive 8 solid-state relays (SSR), or protected through opto-couplers on the board.

The addition of the opto-couplers and SSRs makess this more effective in numerous industrial control applications. The 2120, 2140, 2520, and 2540 chipsets are all available on this version of the controller.


The MotionC-S is another variant of the MotionC board. It is designed primarily to support brushless motor servo control with sinusoidal waveforms.

The MCS2340 uses incremental quadrature encoders for position feedback, as well as 8 channels of high speed 12-bit DAC to generate +-10V phase shifted commutation sinusoidal waveforms. Each axis outputs three pulses or two voltage waveforms. The three pulses are PWM pulses with 120 degrees of phase shift. The two voltage waveforms are commutation DAC sinusoidal voltage waveforms with 120 degrees of phase shift.

Programmable phase count, algorithmic or Hall-Sensor based commutation initialization, commutation angle adjusting, index pulse reference are all supported.

The MCS provides protected inputs, up to 24V, for home switches, line switches, and fault switches on each axis. The MCS also supports other PMD chip sets: MCS2540 (stepper) , and MCS2140 (DC servo).

Other Boards

The MotionC family of boards are high-end solutions to demanding motor control requirements. If your needs are not as demanding, think about using one of TERN’s other programmable embedded controllers for directly driving the motor: for example using the DACs of the R-Drive to drive a servo, or using high-speed TTL I/Os from the 586-Engine to drive a stepper.

MotionC Specs:

  • Measures 4.66×3.75 inches
  • 40 MHz DSP
  • Power: 200 mA at 12V
  • 7 solenoid drivers, 24 free TTL I/Os
  • 2 RS232, 1 RS232/RS485 drivers
  • Temperature: -40 to +85 Celsius
  • Protected inputs for home, limit, capture, and fault switches
  • 32-bit registers for position, velocity, acceleration, and jerk
  • S-curve, trapezoidal, or contoured velocity profile modes
  • Electronic gearing, 1/T counter for stable low velocity
  • PID or PI control, programmable loop rate to 100uS
  • Electronic gearing for multi-axis

21xx version specs:

  • 2 or 4-axis closed-loop brushed servo

25xx version specs:

  • 2 or 4-axis open-loop stepper

P Version Specs (adds):

  • 32 opto-couplers (home, limit, capture, fault switches, 16 I/Os)
  • 8 opto-isolated solid state relays

S Version Specs:

  • Measures 4.5×4.8 inches (larger)
  • Power: 300 mA at 12V
  • 8 ADC, 4 DAC
  • Electronic Gear, PWM, DAC sinusoidal commutation outputs.

Supported controllers: i386-Engine, A-Engine, 586-Engine

MC2120/MC2520  – CALL
MC2140/MC2540 – CALL

Includes Motion control DSP chipset, protected high-voltage inputs, solenoid drivers, 24 I/Os, 2 RS-232, DAC. Does not include controller.

MCP2120/MCP2520 – CALL
MCP2140/MCP2540 – CALL

In addition to above, also includes 32 opto-couplers, 8 solid-state relays. Does not include controller.

MCS -2120/-2520/-2320 – CALL
MCS -2140/-2540/-2340 – CALL

Includes 4-axis control DSP chipset, solenoid drivers, 24 I/Os, 2 RS-232, DAC.

  • 8 ch. 16-bit 100K ADC (LTC1605) $100
  • 4 ch. 12-bit 300K DAC (DAC7625) $60
  • Switching regulator $30.