CPU System

CPU System


Developed from 1999 to 2000, this integrated relay/combination action system, while an evolution of the Copper Box System, takes advantage of the ever increasing capabilities of the microprocessor, memory, and related components to enhance and enlarge all capacities of pipe organ control. The use of parallel processing is unparalleled, as is the use of fiber optic communication to eliminate the backplane/mother/daughter board layout that relies too heavily on plug connectors and long data bus layouts. Three types of circuit cards combine to make this control system for any pipe organ, and it is the ‘programming’ that makes these generic cards into a unique installation. This programming is done by the organ builder after wiring, using the already existing low 8 keys of the Great division keyboard. A partial list of maximum numbers for this CPU system are 9 keying divisions including pedalboard, 128 general and divisional pistons, 128 couplers, 192 stops, 7 swell pedals, and 512 rank outputs. All of the features of the Copper Box system have been retained, enhanced, and increased, both in numbers and ease of use.

The first circuit board is the CPUCPU board or central processing unit, only one is required per pipe organ installation. This controls and stores all aspects of the pipe organ, from coupling to combination action, and record/playback to name a few. It is located in the console where it reads all console inputs, writes to combination action magnet outputs, writes note on/off data to the pipe chambers, writes to the LCD for system status, interfaces directly to MIDIMIDI, and contains non-volatile memory for record/playback.

The second is the Inputinput board which reads all inputs from the console: keyboards, stops, couplers, pistons, and expression pedals. Each board has two unique addresses of 64 pins each, for a total of 128 inputs. These 64 pin address logically allow for 61 note key divisions or other combinations of inputs depending on certain definitions. Each Input board has a microprocessor and a fiber optic receive/transmit link to talk with the CPU board.

The third is the Outputoutput board, interfacing between the CPU and all magnet coils, either in the console for the combination action or in the pipe chambers for windchest and swell shade control. Again, each output card has a microprocessor, a fiber optic receive/transmit to communicate with the CPU board, unique address, and 128 outputs arranged in two groups of 64.

An LCDlcd is used in the console to monitor system status for the organist by indicating all console functions. The organ builder uses this LCD to program these generic Input and Output circuit boards into a unique instrument, and to troubleshoot by monitoring system status. This is the only non-traditional component that is necessary to make visible to the organist.

All of the circuit cards in the console are connected via a single fiber optic loop, thus communicating all data or inputs to the CPU and transmitting all outputs for combination actuation from the CPU. The chamber is connected via a single fiber to receive all note on/off communication from the CPU card.

A fiber optic repeaterfiber optic repeater or conversion board is needed when distances between console and chamber exceed cable lengths of 100’. Plastic fiber optic cable is used when the cable length is less than this 100’ and glass fiber optic cable is required for distances greater than this 100’ threshold. To use glass cable, the plastic fiber needs to be converted to glass fiber, thus requiring one of these boards at each end to convert from plastic to glass and back again to plastic. Also this board can be used as an intermediate repeater to extend the transmission length of plastic cable by retransmitting the data at full strength to offset the light loss inherent in this type of data transmission.

Added in 2003 is the optional AtoDAnalog to Digital or Analog to Digital conversion of the expression pedals through the use of slide or rotary potentiometers to read pedal positions. This single card, which can read up to 8 pedals, is powered by a microprocessor and a fiber optic receive/transmit to communicate with the CPU board.

The LED/photo transistor key contact railKey Contact Rail, added in 2007 as an optional way to wire a keyboard, is an application of the existing Input card to read a keyboard without using mechanical contacts, thus no moving parts to wear out. Functionality is exactly as the existing Input card, the base address reading the keyboard and the base address+1 able to read piston inputs. This eliminates any individual contact wiring and cabling, linked only by power and fiber optics to the CPU card.

The CPxCPx upgrade or replacement for the CPU board occurred in 2012. This surface mount technology board incorporates a USB port for thumb drive or flash drive memory storage of all memory levels and record/playback functionality. Also embedded in this board is the AtoD capability, thus eliminating the need for the optional AtoD board previously used. This upgrade board is fully backward compatible with the CPU/Input/Output layout, but does require the use of potentiometers to read the expression pedal positions.

An upgraded OutputOutput Board board, available in 2013, incorporates the use of surface mount chips and new high current driver chips. These chips, available in either polarity, negative common – high side switching, or positive common – low side switching, can now handle 1.2 amps per pin with no heat rise. Advantages of these new switches are protection against thermal, overload, over current, over voltage, and ESD. The result is a chip that will not be damaged if a magnet coil or output wire is shorted out. Combination action magnets, pull-down magnets, and low resistance pedal action magnets can be controlled with no additional or external components, at 100% duty cycle.