The GM215 is a 7A, 80VDC step motor drive with an integrated motion controller. It can be used as a step and direction input motor drive or as motion control enabled drive. The operating mode and mode related functions are set via the 10-position slide switch on side of the drive. The GM215 has 3 opto-isolated inputs and 3 opto-isolated outputs. The function of the input/outputs is also determined by the selected operating mode. The features of these operating modes are described below. 


The GM215 can operate as a conventional STEP and DIRECTION input step motor drive.

MICROSTEPPING: The GM215 has a 10 microstep native resolution; each full step angle of the motor is divided into 10 equally spaced microsteps so a 200 step per revolution motor has 2000 stopping locations per revolution.

STEP PULSE MULTIPLIER: The GM215 synthesizes 10 microstep pulses for every full-step pulse and 5 microstep pulses for half-step pulse. The GM215 acts like a full or half-step drive but motor has the smoothness of a 10-microstep drive.

SUB-MICROSTEPPING: For the 10 microstep resolution, each input step pulse is divided into 32 sub-microsteps resulting in a motor smoothness equal to a 320 microstep drive.

MORPHING: The GM215 morphs from sine-cosine motor currents at low speeds to square-wave currents at high speeds. This technique extracts the maximum possible power from the motor at higher speeds. Morphing begins at 240RPM and ends at 360RPM.

MID-BAND RESONANCE COMPENSATION: The GM215 uses active second-order damping to completely suppress a step motor’s tendency to resonate and stall at medium speeds (300RPM – 900RPM). This results in stable motor operation in this region.

LOW SPEED RESONANCE COMPENSATION: Low speed resonances are motor vibrations at speeds below 120 RPM caused by motor non-linearity. The PROFILE and ADJUST trimpots settings nulls these vibrations.

PROTECTION: The GM215 is protected against motor to ground and motor to motor output short-circuits. It is also protected against reversed power supply polarity and power supply over-voltage. The internal fuse blows on polarity reversal and over-voltage.

AUTOMATIC STANDBY CURRENT: If enabled, the motor phase current is reduced to 70% of the set value and the GM215 motor switching topology is changed to a low heating recirculating mode. This happens 1 second after the last step pulse is received.



The GM215 motion controller core is a 16-bit MCU, FPGA, Flash ROM and an RS485 interface transceiver. The motion controller executes ASCII format commands sent from an external PC or from its own non-volatile memory.

'ON THE FLY' MOTION CONTROL: Acceleration, velocity and destination can be changed even while the motor is in motion. The new values apply immediately.

MULTIPLE AXIS MOTION: Up to 4 GM215 drives can communicate with each other to execute coordinated multi-axis motion.

RUN FROM STORED PROGRAM: The GM215 can run stored motion programs from its non-volatile Flash memory without a computer connected to it. The memory can store over 65,000 coordinates or program lines.

POWERFUL COMMAND-SET: The command-set includes 'if-then-else' conditional branching, looping and macros (subroutines). It also includes canned high-speed HOME routines, JOG routines, SPEED control routines and more.

ANALOG INPUTS: The GM215 has three on-board trimpots to allow setting acceleration, velocity and destination instead of using digital settings.

GENERAL PURPOSE I/O: The GM215 has three opto-isolated user defined inputs and three opto-isolated user defined outputs.

RS-485 INTERFACE: The GM215 has an RS485 interface available. The default baud rate is 115,200.

BOOT-LOADER: The user can update the GM215 firmware using the built in boot-loader function.


CN1 CONNECTOR ASSIGNMENTS                                                                                                                                                         

     Terminal             Name                      Function

                1              GND                        DC Power supply (-)

                2              VDC+                       DC Power supply (+)

                3              A                             Motor winding A

                4              /A                            Motor winding A

                5              B                             Motor winding B

                6              /B                            Motor winding B



Connect the power supply '-' to this terminal. This connection must be hard-wired to the power supply.


Connect the power supply '+' to this terminal. The power supply voltage must be between 18 VDC and 80 VDC and this connection must be hard-wired to the power supply. Do not use a switch, relay contact or any other device in series with this wired connection.



Connect one motor phase winding to these terminals.



Connect the other motor phase winding to these terminals.


TRIM1 and TRIM2 are used to maximize motor smoothness at speeds below 50 RPM. The Digital Self-Test feature can useful in making these adjustments. While the motor is turning, adjust TRIM1 for minimum motor vibration.

The rest of this user's manual is divided into two sections. Use the GM215 STEP MOTOR DRIVE MANUAL if the GM215 is used as a conventional step motor drive. Use the GM215 MOTION CONTROLLER MANUAL if the GM215 motion controller is used.