DMX Motion Control

Fineline Solutions has developed an extensive software library designed to bridge the gap between industrial motors and conventional theatre or touring controls. This allows larger items of set to be controlled with relative ease, and to be synchronised with other lighting states. We also have design experience which allows us to assist with the specification of motors, gearboxes and mounting hardware. This technology can be used for a variety of purposes, for example:

  • Track-mounted, moveable carriages to support video screens, lighting equipment, set pieces etc.
  • Venetian blinds
  • Roller blinds
  • Searchlight automation

Although every system is unique, Fineline Solutions have worked to produce software and hardware modules which may be reused in other systems. This approach ensures that we are able to build custom systems quickly using tried and tested technology. Our experienced engineers will be happy to work with you to design a system to meet your requirements.

Types of system

Our motion control technology can be applied to almost any kind of system, from simple single-motor applications to systems involving several motors in different locations. By using industrial motors and drives, larger loads can be accommodated with ease, opening up possibilities for automation of set components, video screens and even large lighting fixtures.

Simpler systems are usually based around one or more axes of motion, and typically remain in a fixed location during use, for instance a large lighting fixture or a blind module. More complicated systems might involve a track-mounted carriage – for instance being used to suspend a video screen or set item. Carriages can contain several axes of movement, for instance rotating the screen to ensure that it faces the audience when moving around a curved track. Our control systems are able to manage several carriages on the same track, ensuring that they maintain a suitable separation even if one carriage becomes disabled on the track.

Mechanical

Any motor-driven system will need to carefully consider mechanical requirements to ensure satisfactory operation. Ultimately, each motor needs to move a load, which must take place over a particular time. The characteristics of the load and the speed of operation determine the type of gearing arrangement and the size of the motor. In addition, the type of load will also determine how the system will behave under acceleration and deceleration: the motor system will need to be designed to overcome this inertia without overshooting (or undershooting) the target position.

The structure used to support the load, motor and gearbox combination will also play a large part in the stability of the system. A structure which is too weak or not sufficiently stiff can negatively affect the system response. Each system design is ultimately a compromise between speed of motion and stability, and our engineers will be able to work with you to determine the best choices of motor, gearing and structure for your application.

Control

Our control systems are designed to allow the end user to either define a set of preset positions and moves, or to allow them to directly move motors under fader control. The system is able to work in either linear units or rotational units. Linear units would typically be used in a track-based system, measuring the distance along the track in millimetres. Rotational units would be used for circular motion, measuring the movement in degrees.

The control system offers two methods of control using a simple web interface. One method allows positions to be preset using the web interface, and recalled via a fader value. The second method allows a fader to directly control each motor, the control system mapping a defined movement range to a fader. For instance, 0% might be mapped to a position of 2m along a track, and 100% might equate to 12.25m along the track. Fading between 0% and 100% will move the carriage between the two positions.

When multiple carriages operate on the same track, the control system allows a dynamic ‘safety zone’ to be defined for each carriage, preventing adjacent carriages from getting too close. This can be used to ensure that set items or video screens attached to the carriage do not bump.

Our control systems typically connect to the motor drive using wired Ethernet. This method allows a single controller to manage a network of motor drives, and also enables technologies such as software gearing for very large systems. However, for track-based applications, it is often problematic to have a trailing cable. In this case, we often use a conductor rail system for power and communications. We can situate a controller on each carriage, and use the conductor rail to communicate between the central controller and adjacent carriages.

Power and communications

Power and communication requirements vary considerably between systems. In some applications, it is possible to run Ethernet and power cable to each motor drive. In systems where it is not possible to use trailing cables, we would use either a slip ring for circular motion, or a conductor rail for linear tracks. Both solutions can be used to transfer both power and communications data to the device under control.

Safety

For safety, all systems self-monitor the position and operating parameters of the motors under control. If a position or parameter is out of range (for instance an excessive load on the motor indicates an obstruction), the system will fail safe and stop all motion. Depending on the application, a dead-man’s handle can be provided, requiring an operator to keep a button pressed for the duration of the move.

We also specify Emergency Stop buttons according to the ISO 13850:2008 Safety of Machinery – Emergency Stop – Principles of Design standard. The standard requires the provision of clearly-identifiable, latchable emergency stop buttons which may be operated in the event of an unsafe situation arising. The standard also requires that the system will not resume motion following an emergency stop until the operator has confirmed that motion should resume.

Diagnostics

Our control systems provide a web-based diagnostics and configuration interface, which displays useful operating parameters and positions for all motors controlled by the system. This interface can be used during troubleshooting, for instance to determine whether a particular carriage is online, or whether a motor has overheated. The web interface also allows motors to be driven outside defined limits under operator supervision. This is useful for diagnostic purposes, or if a carriage needs to be removed from the track for any reason.

Further information

For further information, or to discuss a project involving DMX motion control, please contact Fineline Solutions.