Digital Stepper Drive

The Gemini GT is the digital stepper drive member of the Gemini Family. The Gemini GT is easily configurable and programmable via RS232/485 using Compumotor’s Motion Planner TM on a PC or Pocket Motion Planner TM on a Window’s CE-based palm PC. The Gemini GT is an alternative to a digital servo drive. With breakthrough techniques such as Encoderless Stall Detect TM and ABS damping TM (patents pending), the Gemini GT provides servo like performance with the lower motor price of a stepper system. With the same connectivity, configurations, and family feature set as the Gemini GV, the Gemini GT allows for an easy upgrade path to the Gemini GV digital servo drive.

Active Damping TM, Electronic Viscosity TM and ABS Damping TM

The Gemini GT follows in the footsteps of Compumotor’s ZETA drive family and offers Active Damping TM (patented) and Electronic Viscosity TM (patent pending). The Gemini GT goes one step further with ABS Damping TM (patent pending). This damping feature is for speed ranges from 0 to 0.1 revs/sec. This "no-fuss" feature requires no user set up and dramatically reduces settling time.

Encoderless Stall Detect TM

Encoderless Stall Detect TM allows detection of a motor stall without adding an encoder to an application. Stall conditions result from inequality of commanded velocity to actual velocity at the motor shaft, regardless of physical reason. The user will be alerted to a stall condition via LED, digital output, or via query over the communication port. Stall sensitivity can be adjusted with a single parameter.

Features

Gemini GT Performance

• Provides four power ranges for up to 8 Amps of continuous current
• Step and direction (cw/ccw), +/- 10 VDC velocity, and encoder tracking modes available
• Active Damping TM , Electronic Viscocity TM, and ABS Damping TM
• Encoderless Stall Detect TM
• Simplified configuration
• Variable resolution up to 128,000 steps/rev

Gemini GT Protection

• Short circuit protection -- phase-to-phase and phase-to-ground
• Brownout protection -- if AC drops below 85 VAC
• Over temperature -- shutdown occurs at ambient 131F (55C)

Gemini GT Physical

• A wide selection of stepper motors are available from Compumotor including the O, R, T, and E Series
• Two input power ranges available; low: 120V, and universal: 120/240V
• Diagnostic LEDs for drive status, firmware download, and optional keep alive mode

Gemini Family Features

• 24V Keep Alive (not required) -- keeps logic alive if AC power is removed
• Error Log - records 10 most recent errors with time stamp
• Approvals: UL Recognition, cUL, CE (LVD), and CE (EMC)
• Configurable via RS232/485 using Compumotor’s Motion Planner TM on a PC or Pocket Motion Planner TM on a Windows CE-based Palm PC

  When Can I Take Advantage of a Low-Cost Stepper Motor?

  Applications with...
  • Predictable loads
  • High stiffness at rest required
  • High accuracy, resolution, and reliability required
  • Continuous power needs
  • Speed less than 50 rps

  Additional References

  • GT/GT6 Common Specifications
  • GT6 Commands and Capabilities
  • Stepper Speed/Torque Performance Curves
  • Stepper Motor Specifications
  • Stepper Motor Dimensions & Drawings
  • Stepper Motor Ordering Information
  • Gemini GT and GT6 Connections and LEDs
  • Gemini Dimensional Drawings
  • Ordering Information and Part Numbers
  • User guide
  • Support and sample files