Copley Controls: Stepnet Module (STM Series)

20-75 VDC & 115-230 VAC Digital Drives for Stepper Motors

Description

Stepnet is a stepper motor drive that combines CANopen networking with 100% digital control of stepper motors. When used with Copley’s Accelnet™ and Xenus™ digital servo drives it enables brushless, brush, and now stepper motors to be controlled over the same distributed network.

In addition to CANopen motion commands, Stepnet can operate as a stand-alone drive. Inputs can be incremental position commands from controllers in Step/Direction or CU/CD format, as well as A/B quadrature commands from a master-encoder. Step to motor position ratio is programmable for electronic gearing.

The RoHS version has a ±10V analog input for position/velocity/torque control. This enhances the ability of the driver to work with external motion controllers which can control steppers using Stepnet in servo-mode.

Setup is fast and simple using CME 2™ software operating under Windows® and communicating with Stepnet via an RS-232 link. CAN address selection is by digital inputs.

Stepnet operates as a Motion Control Device under the DSP-402 protocol of the CANopen DS-301 V4.01 (EN 50325-4) application layer. DSP-402 modes supported include: Profile Position Mode, Interpolated Position Mode (PVT), and Homing Mode.

Profile Position Mode does a complete motion index on command with S-curve acceleration & deceleration, top speed, and distance programmable. In PVT mode, the controller sends out a sequence of points each of which is an increment of a larger, more complex move than that of a single index or profile. The drive then uses cubic polynomial interpolation to “connect the dots” such that the motor reaches each point (Position) at the specified velocity (Velocity) at the prescribed time (Time). Homing mode is configurable to work with a combination of limit and home switches such that the drive moves the motor into a position that has an absolute reference to some part of the machine.

There are twelve logic inputs. Eleven are programmable as limit & home switches, stepper pulse inputs, A/B encoder, reset, or motor temperature. Another dedicated input is for drive Enable. There are four programmable logic outputs for reporting a drive fault, or other status indications.

An Aux HV input is provided for “keep alive” power that preserves the drive data (e.g. current position) and CANopen operation if +HV has been removed as in an emergency-stop situation. This enables the control system to monitor drive status and to enable an orderly recovery without a full system reset, and “homing” of all axes.

Operation from transformer-isolated DC power supplies saves cost in multi-axis systems.

Control Modes

Command Interface

Communications

Feedback

I/O - Digital

Dimensions: mm [in]

* Available on RoHS version