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Single-plug connections between controls and amps minimize the wiring complexity in large systems. A single fiber optic strand can provide a controller with: position feedback, flag status (limits, home flag, registration prox status), amp status, and machine input status. This same strand can communicate to the amplifier and other devices on the MACRO network. (Amp enable & amp command signals, machine outputs, commands to D/A converters, all can be implemented with a single plug connection.) Setup and initialization information for amps and other devices also can be transmitted through the strand, eliminating in many cases the need for separate RS232 cables. Less wiring translates into faster machine assembly, lower assembly costs, fewer errors, and easier trouble-shooting in the field.
Noise Immunity. Fiber-optic cable transmits light, not electricity. Unlike electricity, light is immune to electromagnetic noise, capacitive coupling, ground loops, and other wiring nightmares. The copper based system is transformer isolated for better noise immunity.
Speed. One of MACRO's most impressive features is it's 125 Mbits/Sec rate of data transmission. This is at least 25 times faster than most other digital motion control interfaces. What good is all this speed? Well, take the case of a system with 16 amplifiers and two 8-axis controllers. Updates to each amplifier and controller can occur at less than 25 m sec intervals (>40kHz). This is more than fast enough to close high performance servo loops across the MACRO ring, allowing the flexibility to choose distributed intelligence or centralized control!
Digital communications allows the ability to "tie it all together". In a motion control application there are a number of different tasks: trajectory planning, position loop closure, velocity loop closure, current loop closure, and commutation (if the motor is Brushless or AC Induction - flux-vector controlled). Controllers have always performed trajectory planning and position loop closure digitally. Today, many controllers are also closing the velocity loops digitally as well. Amplifiers are also changing with the times. AC Servo and Vector amplifiers have always performed their commutation functions digitally; however several amplifiers now close their current loops digitally as well. Digital communications allows the ability to tie all these tasks together without conversion to the analog realm. This can improve system performance by minimizing error in D-to-A, and A-to-D conversion, eliminating ground loops and voltage offset/shift problems. It also allows adaptive control techniques, enhances the ability to analyze & critique system performance using techniques like data-gathering, and even provides the potential to auto-diagnose a system problem from a central or supervisory control.
One ring, multiple masters. In a ring topology, a central control serially transmits information to several nodes (see illustration). Today's multi-axis controls typically support only 4 to 8 axes. In machines with more than 8 axes, having a ring for each control is sometimes not desirable. In these cases MACRO will support the ability to put several of these controllers ("masters") together on one ring, further simplifying the system complexity.
Simplicity. Transmission across the MACRO ring requires no software intervention. The information to be sent from one node to another is merely written to a memory location, and the MACRO hardware takes care of the rest. A programmer does not need to worry about slipping "telegrams" into the timing of the ring communications, or interrupting a task to update the ring.
What
industries/applications does MACRO support?
MACRO lends itself well to large multi-axis applications where the amplifiers and I/O are spread out in several cabinets around the machine. Packaging, converting, processing, and textiles machinery as well as robotics systems, and automated assembly lines all can benefit from MACRO's advantages.
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