AEROSOFT. Aerosoft Australia Introduction. MCP Overview. About Us. What is it and what does it do? What simulation software interfaces with it?

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Joan Arnold
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Aerosoft Australia Introduction About Us Aerosoft Australia has been developing products since the early 1990 s and is located in Sydney Australia.

Following that was a product called SatNav which interfaced to a GPS system and displayed a 3D representation of the world and flight plan on a computer screen.

1 Aerosoft Australia Introduction About Us Aerosoft Australia has been developing products since the early 1990 s and is located in Sydney Australia. The first software title produced was for night VFR training that helped pilots practise NDB and VOR intercepts. Following that was a product called SatNav which interfaced to a GPS system and displayed a 3D representation of the world and flight plan on a computer screen. After a short break we were interested in building a full size 747 cockpit for fun. As it turned out we thought that might have been a little ambitious so we decided on a Piper Arrow cockpit instead. In retrospect, the would have been an easier project. Flying schools around the world and individuals use the Piper Arrow for fun and flying training. Our latest product is the 747 MCP and that s what will be discussed here. MCP Overview Documents exist on our web site that describe operation of the MCP so this discussion is intended to me more of a look under the hood of the MCP and how it works. What is it and what does it do? The letters MCP stand for Mode Control Panel and it s basically part of the autopilot/auto flight system found on the Boeing aircraft. It can control aircraft speed using aircraft throttles, aircraft heading, aircraft altitude, climb and descent rates, capture of airport localiser and glide slope, as well as lateral and vertical navigation when used in conjunction with a the flight management system. It has a variety of controls such as toggle switches, push buttons, rotary controls and numeric displays. The unit is approximately 430mm or 17 inches wide, and 76mm or 3 inches high. It is found in the flight deck mounted in the glare shield in easy arms reach of both pilots. What simulation software interfaces with it? Our MCP has been designed to interface to a variety of software including the following titles: Microsoft Flight Simulator 2002, Aerowinx PS1, Project Magenta and Wilco Pilot in Command 767. Although the Wilco PIC767 models a Boeing 767, the PAGE 1

2 operation and layout of the two MCPs are almost identical. In fact, the 757 MCP is similar also. We wrote software for the Aerowinx PS1 simulator that was compiled directly into the PS1 core product by Hardy Heinlin. Laurent Crenier from the PIC767 project wrote an interface DLL for us and Enrico Schiratti provided information on interfacing with his glass cockpit products. Pete Dowson supplied the invaluable FSUIPC software for FS2002. Central to the software mentioned, with the exception of Aerowinx PS1, is our own software that talks directly with the MCP hardware and interfaces to the titles listed above. MCP Design Philosophy Expandable We originally conceived the MCP to be an add-on product that would interface to a central black box that contained electronics for interfacing external hardware. However, to make the black box useful, a user would have to purchase the black box electronics and a panel to interface with it. That meant two products. We didn t like that idea and instead incorporated the electronics and panel hardware into one unit, the MCP. It was our goal with the original design to provide an upgrade path. We thought that if our dream to build a complete 747 flight deck was ever going to happen then we needed something that was expandable. So, we added a range of digital and analog expansion ports to the rear of the unit, as well as the capability to drive LED based products, like annuciator panels and radio panels. We like to think that the MCP is now the hub for future products. Open System We wanted to build an open system whereby electronic enthusiasts at home could interface their own panels. This is possible with our system since the interface uses a simple switch input matrix that will be discussed shortly. Those inputs can then be mapped to a function in Microsoft Flight Simulator Analog inputs can also connected to the system. We decided to use standard connectors that were available anywhere, namely the DB15 and DB25 connectors. Plug and Play Another philosophy behind the design was that it had to be simple to connect and work straight out of the box. We think we ve met that goal by providing not only a RS232 COM port interface but a USB interface as well. Installation is as simple as plugging the unit in and switching it on. It had to be easy to use and accessible to everyone regardless of his or her computer background. PAGE 2

Smart PC Software Even though the MCP is quite clever, the logic for aircraft functionality is contained entirely on the PC. The reason for this is two fold.

Secondly, it means that our interface software running on the PC can evolve and be easily downloaded without the need for a firmware upgrade of the MCP.

3 Smart PC Software Even though the MCP is quite clever, the logic for aircraft functionality is contained entirely on the PC. The reason for this is two fold. Firstly, this means we can interface to a variety of 3 rd party software. Secondly, it means that our interface software running on the PC can evolve and be easily downloaded without the need for a firmware upgrade of the MCP. It s good to think of the MCP as a system that can accept commands to turn LED indicators on and off, as well as send information to the PC about a switch position or a counter value. Considerations Price With any commercial product price is of the utmost importance. We think we ve provided value for money since the product can be used straight out of the box, can be used with a variety of software, and has a future upgrade path. The MCP uses raised membrane switches instead of push buttons switches. The membrane switch still gives a tactile feel when pushed and since they re raised they re easily located. We wanted to go for as mush realism as we could for the price and unfortunately real switches would have been very expensive. When you consider there are 13 switches the price can add up. Performance Even though computers nowadays are incredibly fast we didn t want to rely on a host system to do the work. So, integrated into the MCP is a microprocessor that does all of the work. It s responsible for communicating with the host PC via RS232 and USB, scanning switches inputs, displaying LED outputs and controlling the rotary inputs for displays such as heading and altitude. The MCP takes care of the rotary inputs by automatically counting up and down when you turn a rotary knob. In practical terms this means you get a fast, crisp response when adjusting a numeric display. Realism Aircraft parts are incredibly expensive and generally unobtainable. We ve tried to match as best as possible, for a reasonable price, the look and feel of the real aircraft. When flying with the MCP you still get the sensation of precision and control over the aircraft you re flying. External hardware gives feeling of being immersed in the simulation. PAGE 3

Capabilities Ok, now on to some of the capabilities of the system. As mentioned, the system is open and expandable and we ll take a look at the capabilities in depth.

4 Capabilities Ok, now on to some of the capabilities of the system. As mentioned, the system is open and expandable and we ll take a look at the capabilities in depth. Expansion Inputs Time for some numbers. The MCP has 4 expansion ports on the rear panel. These are in the form of a 25-pin DB25 connector. Again, where possible we use standard computer parts. The reason is that cables and connectors are readily available. Each expansion input can accept 72 switch inputs. The switches can be of any type; momentary, rotary, toggle etc. Switch inputs are arranged in a 12 by 6 switch matrix. We call the 12 inputs switch inputs and the other 6 inputs scan lines. 12 switches can be connected to one scan line. Since we use a number of switches on one scan line, we must electrically separate the 12 switches from each other. Placing diodes between each switch and its scan line achieves this. If you are building your own input circuit these are mandatory otherwise an electrical short will occur and damage the MCP. Analog Inputs An analog device can be thought of as an input that has a variable range. A throttle or elevator control is a good example of an analog input. The MCP is capable of processing input from a total of 16 analog devices. We split the analog inputs over 4 DB15 connectors, giving us 4 analog inputs per connector. These connectors are the same as those used for joystick input on the back of your PC. It is entirely possible to plug a standard game port joystick into the back of the MCP and use it. However, we recommend that you use your current joystick set-up on the PC connector rather than the MCP. Why? Simply to keep the joystick ports free for future expansion. There s no real need to move a joystick with elevator and aileron control from your PC to the MCP. The MCP is better suited to handling more complicated devices like rudder pedals with individual toe brakes. You can also connect other devices which are not actual joysticks using the DB15 connectors. If you were building a 4-lever throttle each input can be connected to one DB15 connector. What is the electrical part that should be connected to a mechanical throttle? A 100k ohm potentiometer. Most joysticks use a 100k ohm potentiometer and we ve optimised our firmware to accept this type of input. 100k ohm potentiometers are very easy to find at most electronic shops and connecting them is a simple 2-wire operation. The analog inputs also have provision for 4 switch inputs per port. You can use the buttons on your standard joystick and assign them to functions within FS2002. LED outputs An LED is a light emitting device and is much more reliable than traditional light globes. We use LEDs throughout the MCP. A LED can come in a number of forms, from square, to round, to numeric and alphanumeric displays. Internally, the MCP PAGE 4

5 actually has 65 domed LEDs arranged with 5 per mode button. It also has sixteen 7- segment displays that are used in the numeric display windows. Any sort of expansion system would not be complete unless it had output as well. Output is generally in the form of an indicator to a pilot. This could be a thrust reverser light or a warning indicator. With the MCP we have the capability of controlling external LEDs, however a MAX7219 chip on external circuitry must be used. Without going into too much technical detail, this chip can display up 64 individual LEDs. Each expansion port has 3 pins dedicated to talking to the MAX chip. A total of up to 6 MAX chips can be connected per port and that means you can control 384 individual LEDs per port. They may sound a little excessive but when using a 7-segment display for numerical information, 8 of these outputs are used for one number. In other words, each expansion port can display up to 48 numbers. A DME readout, or a radio frequency would be a example of where to use the 7- segment displays. The way LEDs should be connected is like Christmas tree lights, in a long string from beginning to end. Each MAX display chip is cascaded down to the next chip and the data for each LED display is output in a serial stream. Sounds complicated? With our software assigning LED data is easy. CPU and Firmware The MCP is not just a box with displays and switches. To add functionality and control of the expansion ports we require the use of a microprocessor. The MCP has a microprocessor which controls the USB and RS232 serial port, scans for switches being pushed, converts analog input to digital data for joystick control, handles the update of the MCP displays, controls LED output on the expansion ports as well as expansion port switch inputs. All microprocessors need software and the MCP is no exception. Software inside the MCP is called firmware and this is the program that is inserted into read-only memory. When the power is turned off, the software is not lost and remains in the read-only memory. With our MCP we will occasionally update the firmware to introduce new features or correct bugs. Firmware can be updated via the USB port or serial port. It s a simple matter of running our special PC software that uploads the firmware to the MCP. Interaction the PC Methodology We know that the MCP uses a microprocessor that enables us to talk efficiently to the PC but how does the communication take place? We ve designed a serial communication protocol that the MCP understands and our interface software understands. The MCP can send a command to the PC, and the PC can send a command to the MCP. When a button on the front panel is pushed for example, the button number is sent to the PC. The PC in turn processes an appropriate response for that command and sends it to the simulation. PAGE 5

In real MCP operations the IAS/MACH display and VERT SPD display can be blanked. Again using the same protocol the MCP receives a command from the PC and blanks the display.

6 In real MCP operations the IAS/MACH display and VERT SPD display can be blanked. Again using the same protocol the MCP receives a command from the PC and blanks the display. The PC can also program the value of the numeric displays and of course can turn on any of the 13 mode indicators. Round trip communication The MCP does not think as such. When you press a button on the front panel that has an associated LED indicator, the indicator is not turned on when the button is pushed. Instead, the command that a button has been pressed is sent to the PC and the PC decides whether or not to turn on the indicator. This means that ultimately the PC has control of the function of the MCP panel. Enhanced Rotary Controls When we use a round trip scheme to transmit commands to the PC there is a very slight delay, typically less than 1/15 th of a second. Normally this is imperceptible if you re only pushing a button. However, with a rotary control like IAS/MACH, HDG and ALT a delay when adjusting them would be undesirable. Let s use an example. Imagine using the knob to change from say a heading of 30 degrees to 180 degrees. That s a change of 150 degrees. If the round trip communication takes 1/15 th of a second, we could only send 15 degrees a second, which means it would take 10 seconds to change heading from 30 degrees to 180 degrees! We were aware of this before design took place so instead put some smart software inside the MCP to take care of this. Each rotary control is updated internally. You can adjust the controls as fast as you like and the MCP will never miss an update. As the control is turned the PC is updated with the new control value. We call these rotary controls counters. The counters inside the MCP can be set to a range, like 100 to 399kts for example. Basically the counters know how to count and how to update the internal MCP displays. This is the reason you can turn the rotary controls without FS2002 connected and watch the displays change. Software Interface with FS2002 using FSUIPC FSUIPC stands for Flight Simulator Universal Inter-Process Communication. It is the interface between FS2002 and just about all other 3 rd party software interfaced with FS2002 uses it. It s a DLL that resides in the modules directory of FS2002 and without it operation of the MCP would not be possible. Pete Dowson is the developer and has continued to update the software over many years from FS98, FS2000 to FS2002. PAGE 6

We don t use a simple keyboard key press to interact with FS2002. Instead, we use FSUIPC to get directly at the internal structures and functions of FS2002.

7 We don t use a simple keyboard key press to interact with FS2002. Instead, we use FSUIPC to get directly at the internal structures and functions of FS2002. By using this method we can get complete control over the simulation. Aerosoft Australia MCP Software Interface Our interface software is an application that talks to FSUIPC, which in turn talks to FS2002. Our software has access to almost all parts of FS2002 and can control many internal FS2002 functions. Some of these are the flaps, gear, radio frequencies, individual engines, pause and slew, aileron, elevator, autopilot, clouds, wind, rain etc. With FSUIPC most of the internal systems of FS2002 are available. From our software the MCP can be used as a standard FS2002 autopilot, a real 767 autopilot through PIC767, and the same with the Project Magenta MCP. Our software also maps switches and analog controls to a control in FS2002. External System Integration The MCP has been designed to be expandable and as such means you can add your own home built flight deck switches and interface them to the MCP. It also means we can supply you with additional aircraft systems if you don t wish to build them yourself. Above all we ve always adopted the philosophy of no programming. We ve designed a system whereby you simply plug in your hardware, assign the buttons, and start flying. However, external electronic circuits are required which you can either build yourself or obtain from us. Switches Switches can be connected to the MCP via our switch expansion board. The expansion board plugs into any expansion port on the back panel of the MCP. Switches are then connected using 10-way ribbon cable to the expansion port. If you can solder two wires together, you can interface an external switch. A switch can be of any type; momentary, toggle or rotary. Any type of contact can be used and you re not limited to the switch type. A switch with say 12 positions can be used, or a push-in and lock switch. The way the switch behaves is set up when you assign that switch in software. Our software has the capability of repeating switch commands. For example, you may wish to assign a switch for elevator trim that activates when held, and stops trimming when released. We can also replicate a keyboard press. An external switch can send a command to FS2002 as though a key has been pressed on the keyboard. However, the preferred method of communication is to use the FS2002 function from the list provided. PAGE 7

8 Joysticks Joysticks is probably the wrong word to use for the 16 analog inputs but it conveys quite well the function of the ports. As mentioned earlier, a 100k ohm potentiometer (or of course a joystick) can be connected and calibrated to the MCP. The joystick is then assigned a function from our list of pre-determined aircraft controls. We ve added a S-curve to the inputs on the joystick. This is effectively a sine wave function that means controls can have a fine response around the centre point, and as the control is deflected the response becomes coarser. This allows for a fine control of ailerons and elevators with good user input on the controls. LED output LED assignment is similar to switch assignment except that you re display information on an indicator. An LED can be turned on or off when a certain condition is met within FS2002. For example, the 3 green gear lights can be turned on and off when the gear is up or down. The LED output is not connected to whether a switch is turned on or off, but instead to the internal systems logic of FS2002. In the example of the gear lights, the LED will only illuminate when each wheel of the aircraft has been extended. To help mapping LED displays to commands in FS2002, you simply select the function in FS2002 you wish to map and use the mouse to turn the physical LED on. You can turn on a single LED for the FS2002 function, or a group of LEDs for the FS2002 function, so long as the LEDs are grouped together. Future Directions Hardware Our goal is to supply more aircraft modules and bring more and more of the aircraft systems to the user. The ones in the immediate future are the EFIS and EICAS systems. We re also looking closely at a CDU that again will be a stand-alone unit that is plug and play compatible. Although not designed to plug into the back of the MCP it will be compatible with the software. A CDU in a real aircraft often controls the navigation radios. However, we re looking at building a simple radio stack, in Boeing colours, which will allow you to tune COM1, COM2, NAV1, NAV2, ADF and transponder. We re also looking at controlling OBS1, OBS2, heading bug and altimeter sub-scale from the hardware. Moving away slightly from the electronic systems we ll be looking at a 747 throttle quadrant, available with or without auto-throttle. With an auto-throttle system, electric motors move the thrust leavers to command a desired airspeed. Motors and motor electronics and support hardware is generally expensive and the version without motors will be a less expensive version. Of course, these are all ideas rather than firm plans and it should be understood that we may not bring them to production. PAGE 8

9 Software Something we re thinking about for the future is an aircraft systems software module that s fully integrated fully into our existing interface software. It will contain things like pneumatics, hydraulics and electrics. What will this be used for? To simulate aircraft systems that are not available in FS2002. For example, starting an engine in FS2002 is as simple as pressing a button. In an actual aircraft the electrical system must be brought on-line, the APU must be started, the generators brought on-line, fuel valves opened, fuel pumps started, air introduced into the engines to start the fan rotating, and finally the fuel introduced into the engine to start it. Connecting these switches to the MCP is possible via the expansion interface but software proposed above is required to make a truly realistic aircraft environment. Summary We ve designed the MCP to be upgradeable by way of firmware updates. It s expandable with its 4 expansion ports and 4 joystick ports. The MCP has been designed as a hub for complete flight deck integration. We provide free software updates as well as an interface to a range of 3 rd party systems. PAGE 9

JetMax Throttle Installation Instructions

JetMax Throttle Installation Instructions 1 The JetMax 737 Throttle unit is designed to bring our customers a highly realistic looking device that covers all the basic requirements needed! Features Include: