PI C-663.12 Mercury Step Motor Controller

Mercury Step motion controller analysis: an engineering tool driven by high-precision stepper motors

In the field of modern precision motion control, stepper motors are widely used in optical positioning, automated testing, semiconductor manufacturing, and biomedical engineering due to their advantages of open-loop controllability, accurate positioning, and moderate cost. However, traditional open-loop stepper systems are prone to problems such as step loss, heating, and resonance during high-speed, variable load, or long-term operation. To overcome these bottlenecks, closed-loop stepper control technology has emerged. The Mercury Step single axis stepper motor controller is an outstanding representative of this technology direction. It combines high microsecond resolution, flexible network topology, rich software interfaces, and powerful macro programming capabilities, making it an ideal choice for laboratories and industrial sites to balance performance and usability.

This article will comprehensively analyze the technical connotation and engineering value of the Mercury Step controller from six aspects: hardware architecture, core control functions, interfaces and networks, software ecology, compatible motion platforms, and typical applications.

Hardware architecture and basic specifications

Mercury Step (model C-663.12) is a single axis controller designed specifically for two-phase stepper motors. The core design concept is to support both open-loop and closed-loop operation modes, allowing users to flexibly choose according to the application's requirements for accuracy, reliability, and cost.

1. Driving capability and electrical parameters

Working voltage: 24 V to 48 V DC, powered by the included wide input range power adapter. The high voltage design of 48V significantly improves the high-speed torque and dynamic response of the motor.

Maximum output power: Continuous average power below 48 W, peak power (<2 ms) up to 100 W, sufficient to drive most medium-sized stepper motors.

Each phase current limit: 2.5 A, suitable for common two-phase stepper motors.

Power consumption: Approximately 48 W at full load, only 3 W at no load, and extremely low standby power consumption.

Microstep resolution: up to 1/2048 full step. This extremely high subdivision ratio makes the motor run extremely smoothly, significantly reducing vibration and noise, while achieving sub micron positioning resolution (depending on the lead screw).

2. Physical specifications and environmental adaptability

Dimensions: 130 mm x 76 mm x 40 mm (including mounting rails), compact DIN rail mounting design for easy integration into control cabinets.

Weight: 0.48 kg, lightweight and portable.

Working temperature: 5 ° C to 50 ° C, built-in temperature protection switch, automatically shuts off when overheated, ensuring system safety.

3. Connection between motor and sensor

The controller is connected to the motor and external sensors through the HD Sub-D 26 female interface. This interface integrates motor phase lines, encoder signals, limit switches, and reference point switches, simplifying wiring.

Core Control Function: From Basic Motion to Intelligent Servo

1. Motion trajectory planning

Mercury Step supports point-to-point motion and adopts a trapezoidal velocity curve. Users can independently set the starting speed, maximum speed, acceleration, and deceleration to achieve smooth start stop and avoid impact. This trajectory planning method is extremely practical in applications such as positioning, scanning, and indexing.

2. Closed loop servo characteristics

When used in conjunction with an encoder, the controller has a built-in PID control algorithm, and the servo cycle is only 50 μ s. High real-time feedback adjustment can correct position errors in real time and completely eliminate the risk of step loss. Even under load fluctuations or external disturbances, the system can still maintain accurate trajectory tracking.

Of particular note is that the controller supports parameter changing during operation. This means that users can dynamically adjust PID coefficients, speed, acceleration, etc. without stopping the motion, greatly facilitating system debugging and adaptive control.

3. Out of step detection and security protection

In closed-loop mode, users can set a maximum allowable position error threshold. Once the deviation between the actual position and the commanded position exceeds this value, the controller will automatically stop the motor and output an alarm. This out of step detection function effectively prevents equipment damage caused by mechanical jamming, overload, or encoder failure.

4. Data Recorder

Mercury Step has a built-in data logger that can record key data such as speed, position, and position errors in real-time during operation. This is of great value for system performance analysis, fault diagnosis, and control parameter optimization. Users can export data for offline analysis through software.

5. Quick start of ID chip

The controller supports ID chip detection (with future functionality reserved), aiming to achieve plug and play functionality. When connecting compatible motors or platforms with ID chips, the controller can automatically read their parameters (such as motor phase current, encoder resolution, limit polarity, etc.), greatly reducing system configuration time.

6. Non volatile macro storage and auto start macros

Mercury Step is equipped with a powerful macro command language, allowing users to write complex motion sequences, logical judgments, and I/O control programs, which are stored in the non-volatile memory of the controller. By setting the auto start macro, the system can run independently after power on, without the need to connect to the upper computer. This feature is particularly critical for embedded automation devices such as small sorting machines and automatic sample injectors.

Rich interfaces and flexible network topology

1. Communication interface

Both USB and RS-232 can be used as command interfaces. USB provides high-speed and convenient connections, suitable for laboratory environments; RS-232 is suitable for long-distance or industrial sites.

Controller Network (Daisy Chain): Through dedicated network cables, up to 16 Mercury Step controllers can be connected in series (USB mode) or 6 (RS-232 mode), sharing the same host interface. This daisy chain topology significantly reduces the wiring complexity of multi axis systems, and each controller can be independently addressed, achieving distributed motion control.

2. Sensors and I/O

Encoder input: Supports A/B orthogonal signals, TTL or RS-422 levels, with a maximum input frequency of 60 MHz. This allows the use of high-resolution optical encoders or magnetic grid rulers to achieve nanoscale position feedback.

Limit switch: 2-channel TTL input, programmable polarity, used for forward/reverse limit protection.

Reference point switch: 1-channel TTL input, used for home operation.

Index pulse input: 1 RS-422 input, used to receive the Z-phase index signal of the encoder, achieving high repetition accuracy reference point regression.

Universal I/O cable: 4 analog/digital inputs (0-5V/TTL), 4 digital outputs (TTL). These I/O can be used to control external relays, read sensor status, trigger cameras, or handshake with other automation devices.

3. Manual control interface

Simulated joystick: supports connecting two-dimensional joysticks through Y-shaped cables to achieve manual pulse control. This is very intuitive in applications such as manual alignment and microscope stages.

Button box: Optional button box for jog, step, and reset operations.

Software Ecology and Programming Support

Mercury Step uses PI General Command Set (GCS) as the standard command set. GCS is a unified text instruction language defined by Physical Instruments (PI) company, which is easy to read, cross platform, and package. Users can directly send commands through terminal software such as PiTerminal, or integrate them into custom applications through advanced programming interfaces.

1. Official software tools

PIMikroMove: A graphical user software suitable for system configuration, manual movement, macro editing, and data recording. Most control tasks can be completed without programming.

PiTerminal: A command-line tool used for debugging and sending GCS commands.

2. Drivers and development libraries

LabVIEW driver: Provides complete VIs, making it easy to quickly build measurement and control systems in the NI LabVIEW environment.

Windows and Linux dynamic libraries: support language calls such as C/C++, C #, Python, etc., enabling cross platform application development.

MATLAB library: suitable for scientific computing and algorithm prototype verification.

3. Macro language and independent running

Macro command language supports advanced functions such as conditional jump, loop, variable operation, and waiting for I/O. Users can write complex motion sequences, such as: returning to zero → moving to multiple positions → reading external sensors at each position → judging and branching → outputting results. Macros can be stored in EEPROM and set to run automatically upon startup, enabling the controller to have independent intelligence at the level of a microcontroller.

Compatible sports platforms and application scenarios

The Mercury Step controller is designed specifically to drive two-phase stepper motors, making it compatible with a large number of precision positioning platforms driven by commercially available stepper motors. The document lists the following related product lines (all from physical instrument companies), covering a wide range of needs from micro displacement tables to high load linear actuators:

1. Linear platform and actuator

L-239 high load linear actuator: suitable for high thrust, long stroke industrial positioning.

L-402 miniature linear displacement table: compact in size, suitable for integration into optical or semiconductor devices.

L-406 compact linear displacement table: balancing stroke and external dimensions.

L-509 precision linear displacement table: high rigidity, suitable for general laboratory positioning.

L-511 high-precision linear displacement table: using ball screw and cross roller guide rail, the positioning accuracy can reach sub micron level.

M-126 high-resolution translation stage: With extremely high resolution, it is suitable for applications such as fiber alignment.

M-228/M-229 high-resolution linear actuator (stepper motor): directly connected screw, compact structure.

M-230/M-231/M-232 high-resolution linear actuator (DC/stepper optional): flexibly adaptable to different driving modes.

M-403/M-404 Precision Translation Stage: High cost performance, suitable for routine positioning tasks.

M-406 precision linear displacement table: large stroke, stable and reliable.

M-413/M-414 high load precision displacement table: outstanding load-bearing capacity.

M-451 high load Z-axis displacement table: suitable for vertical lifting applications.

M-505 ball screw micro positioning platform: an economical choice.

M-511/M-521/M-531 high-precision linear positioning station: aimed at high-end scientific research and industrial measurement.

2. Rotating platform

L-611 precision rotary table: 360 ° continuous rotation, used for angle positioning.

M-060/M-061/M-062 precision rotary table: different sizes and torque levels.

M-116 precision rotary table: high resolution, suitable for polarization optical adjustment.

3. Multi axis combination platform

L-731 Precision XY Displacement Table: Two dimensional scanning application.

M-110/M-111/M-112 compact micro translation stage: suitable for multi axis systems with limited space.

Most of these platforms offer optional encoders, limit switches, and ID chips. When paired with the Mercury Step controller, it can leverage all the advantages of closed-loop control, automatic parameter recognition, and more.

Typical application scenarios

1. Alignment of Optics and Photonics

Applications such as fiber optic coupling, silicon optical chip testing, and laser beam collimation require sub micron level positioning accuracy. The high micro step resolution and closed-loop control of Mercury Step ensure long-term stable alignment, avoiding thermal drift and out of step effects.

2. Semiconductor Manufacturing and Testing

Smooth and low-noise movements are required for wafer probe stage, mask alignment, confocal microscope scanning, etc. The combination of 1/2048 micro steps and trapezoidal velocity curve significantly reduces vibration, which is beneficial for high magnification optical imaging.

3. Automated testing and assembly

Through macro programming and I/O control, Mercury Step can independently complete the "picking and placing positioning testing sorting" sequence without the need for real-time connection to the upper computer. Daisy Chain networking further supports multi site parallel operations.

4. General positioning of scientific research laboratories

Whether it's sample scanning in materials science or microinjection in biology, Mercury Step, combined with small displacement stages such as L-402 or M-126, can quickly build compact and cost-effective positioning systems.

5. Education and Training

The controller provides various programming interfaces such as LabVIEW, MATLAB, Python, etc., which are very suitable for experimental teaching in mechatronics and motion control courses. Students can understand concepts such as PID control, interpolation principles, and sensor feedback through practical programming.

Quick Reference Table for Technical Parameters

Project specifications

Number of Drive Axes 1

Motor type: Two phase stepper motor (open-loop or closed-loop)

Microstep resolution 1/2048 full step

Servo characteristic PID, adjustable parameters during operation, servo cycle of 50 μ s

Motion trajectory trapezoidal velocity curve, point-to-point

Encoder input A/B orthogonal, TTL/RS-422，60 MHz

Limit/reference point switch 2 x TTL limit, 1 x TTL reference point, 1 x RS-422 index pulse

Out of step detection with programmable position error threshold, automatically stops running when out of tolerance

Working voltage 24-48 V DC (with power adapter)

Maximum current per phase is 2.5 A

Output power (continuous/peak)<48 W/100 W (<2 ms)

Communication interface USB, RS-232

Networking Capability Daisy Chain: Up to 16 units in USB mode and up to 6 units in RS-232 mode

Universal I/O 4-in (0-5V/TTL), 4-out (TTL)

Manual control analog joystick (Y cable), button box

Software PIMikroMove, PiTerminal, LabVIEW, Windows/Linux dynamic library, MATLAB

Macro function non-volatile storage, automatic macro startup, data logger

Special function ID chip detection (reserved), temperature protection, watchdog timer

Size (including guide rail) 130 mm × 76 mm × 40 mm

Mass 0.48 kg

Working temperature range 5-50 ° C

Order number C-663.12 Mercury Step