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Blaze AHRS-2 / AHRS-4 / MAG-2 Operating Manual

Page 13 

Slip Zero:

This function allows you to set your slip indicator to exactly zero even if your aircraft tends to fly slightly wing down. The
procedure is to place the aircraft in a stable, straight and level attitude during calm flight conditions and then select this
function. To cancel the correction, place your sensor absolutely horizontal (use a spirit level) and select the function
again.

Can Address:

Select the CAN address of the SP-X compass sensor.

Calibrate

This allows calibration of the magnetic sensor.

In-Flight calibration Procedure

Please see documentation supplied with the SP-6 for more information.

Fly the aircraft in safe area where you can perform random banked turns. Do not exceed the safety limits of the aircraft 
during the calibration flight.

Start the calibration in the Compass setup menu by selecting “Calibrate”. The AHRS-2 /
AHRS-4 / MAG-2 will display the compass calibration screen. You should see the compass
heading change to “111” to confirm that calibration has started.

Fly a number of banked 180 or 360 degree turns at different bank angles - i.e. shallow, medium and steep turns. Try to 
add many different pitch attitudes in various orientations relative to the field direction. It does not matter in what order you 
fly the maneuvers. A typical, good calibration tends to take 5-10 minutes of flight.

Do not activate any electrical equipment that creates large magnetic fields during the calibration process (for example 
starter motors, autopilot servos, landing lights etc). The heading starts reading 

111 

after you start calibration. After 36 ini-

tial samples have been collected this changes to 

222

. This should take approximately one turn. Continue the flight

while maneuvering until the heading starts reading normally. This happens once the SP-6 has collected 100 distinctly dif-
ferent magnetic samples. At this point the heading should start showing reasonable numbers. Continue the calibration 
flight, settling into straight and level at intervals on different headings and verify the heading readout against an ACCU-
RATE reference. Continue the flight until you find heading errors that are within 1 to 2 degrees, about the limit one can 
reasonably expect.

When satisfied, end the calibration by selecting “DONE” in the compass calibration menu. This will save the calibration to 
permanent memory in the SP-6. Should you not be able to achieve a good heading readout, please locate the compass to
a better location in the aircraft.

The AHRS-2 / MAG-2 displays the calibration sample count and fit percentage during calibration. The sample count will 
count up to 150 after which new samples replace the oldest samples stored. The fit percentage is a value from 0% to 
100%. The aim is to get to a value as close as possible to 100%. The fit starts displaying other than 0% after the first 36 
samples. Fit values of 98% and higher are considered good. If you cannot achieve this you do not have a good installa-
tion location for your compass. You may still get reasonably good heading accuracy despite a lower fit. However, to en-
sure long term accuracy please consider locating the SP-6 in a better area in your aircraft.

If the readout decreases suddenly by a large amount (for example from 85% to 42%), this is typically caused by a
strong time-variant magnetic field such as can be created by electrical equipment (motors, relays, current flow in cables). 
In such a case please either end and restart the calibration or continue the calibration flight until the fit error is acceptable 
again (the incorrect magnetic sample(s) will eventually be removed). It is advised to locate the interference source and
either move this or the SP-6 to a better location in the aircraft.

Note: should you move the SP-6 to a new location or fit new equipment close to the SP-6 you will have to perform the cal-
ibration again. There is no practical limit as to how many times you can perform and save a new calibration.

Summary of Contents for AHRS-2

Page 1: ... Blaze AHRS 4 Blaze MAG 2 AHRS 2 Artificial Horizon and Magnetic Compass indicator AHRS 4 Self Contained Artificial Horizon Magnetic Compass indicator MAG 2 Magnetic Compass Indicator Operating Manual English 1 06 ...

Page 2: ... Force indication requires the MGL Avionics SP 7 sensor packages AHRS 4 Artificial horizon reference system AHRS display unit with slip indication turn and bank and G Force indication complete with built in attitude sensors The AHRS 4 does not require the MGL Avionics SP 7 sensor package to display attitude Advanced magnetic compass with a course steering feature and slip indication Can be setup a...

Page 3: ...oll through the main displays Artificial horizon compass and turn and bank indicator F1 Up Button Menu System Softkey button Pitch level function 3 1 8 80mm enclosure Can be front or rear mounted Rotary Control Up Down Enter Button Press the rotary control during the normal display screens to access the menu system Rotate anti clockwise for up down menu scrolling F1 Up Button Menu System Softkey b...

Page 4: ...ank indicator or the compass 3 1 Artificial Horizon with Compass Pitch level function Should your aircraft fly nose up or nose down due to trim then you can press the F1 key to level the pitch as displayed on the horizon 3 2 Turn and Bank Indicator Slip indicator A step on the ball slip indicator can be enabled to appear below the horizon and compass displays The source of infor mation for this in...

Page 5: ...ems based on mechanical gyros Simply correct the horizon when you are finished or let the horizon right itself which will happen during straight and level flight Message displayed when the maximum bank pitch or yaw rates have been exceeded 3 3 Digital Compass 3 3 1 Compass Tape The digital compass tape can be displayed in 3 different ways The way the compass is displayed can be setup in the menu s...

Page 6: ...s shown below the heading tape No course steering indicators are shown The current heading is 169 degrees course steering indicators show the need to steer slightly to the right to intercept the course The current heading is 218 degrees course steering indicators show that a large correction to the left is required to intercept the course Each or equals 2 degrees of heading error To cancel the cou...

Page 7: ...d can also be caused by nearby electrical equipment such as radios lamps electronic in strumentation or computers even the ignition systems of engines The AHRS 2 MAG 2 has a compass filter setting which can be set to filter out some of these small fluctuations 3 4 GPS Viewer These display are active when a NMEA compatible GPS receiver is connected to the serial port The following GPS information i...

Page 8: ...he rotary control to navi gate through the menu system 4 1 Exiting the menu system Press the F1 Up button to exit the menu system when the EXIT soft key is shown All changes made during navigation of the menu system will be saved in non volatile memory upon exiting The instrument will not save any changes if you re move power before exiting the menu system ...

Page 9: ...ngles superimposed on the horizon display G Force Select ON if you would like to see the G Force displayed on the horizon display Ground Select the ground color of the horizon A selection between BROWN default or GREEN can be made Turn Select whether you want the turn indicator to be shown on the horizon display screen Turn Rate Select whether you want the turn and bank indicators to show a 1 min ...

Page 10: ... degrees Selecting the pitch zero function will zero the pitch selecting it again will reset the pitch offset value to 0 degrees Bank Zero The bank zero function must be performed with the AHRS perfectly level The AHRS will refuse to perform this operation if the real bank angle is greater than 10 degrees Selecting the bank zero function will zero the bank selecting it again will reset the bank of...

Page 11: ... to be performed once This allows to set a pitch tilt of the AHRS keeping all speed related items affecting the accelerometers aligned correctly Level Calibrate AHRS 4 only This function can be used to level the AHRS It levels bank and pitch and sets the Z axis up down to 1G The level calibrate function here MUST be performed with the AHRS perfectly level i e display in normal orientation at 90 de...

Page 12: ...r location This is only used if you would like the instrument to display true heading True heading is the heading relative to the geographic North Pole Magnetic heading is the heading relative to the mag netic North Pole Variation is expressed in degrees east or west Please note that should you move a long distance you may have to update the variation setting This setting may be ignored if you onl...

Page 13: ... At this point the heading should start showing reasonable numbers Continue the calibration flight settling into straight and level at intervals on different headings and verify the heading readout against an ACCU RATE reference Continue the flight until you find heading errors that are within 1 to 2 degrees about the limit one can reasonably expect When satisfied end the calibration by selecting ...

Page 14: ...ical miles per hour UTC Offset Enter the UTC offset for your location The UTC offset can be adjusted in half an hour increments Mag Var Select manual or automatic magnetic variation Automatic variation is only possible if using an external NMEA compatible GPS receiver Variation Enter the magnetic variation of your location This is only used if you would like the instrument to display true heading ...

Page 15: ...gth Data payload Checksum ETX STX Start of text 0x02 Address unsigned char 8bit Unit address range 0 255 Message Type unsigned char 8bit Specifies the message type Length unsigned char 8bit Length of the data payload does not include the STX Address message type checksum or ETX Data payload Data Checksum unsigned char 8bit XOR of all bytes starting from the unit address to the end of the data payl...

Page 16: ...16 bits Bank Angle in 0 1 degrees Pitch angle Signed Int 16 bits Pitch Angle in 0 1 degrees Yaw Angle Signed Int 16 bits Yaw Angle in 0 1 degrees Slip Signed char 8 bits Slip left right 0 0x80 Attitude Status Unsigned char 8 bits bit 2 set AHRS overrange Heading Unsigned Int 16 bits Heading in 0 1 degrees G Force Signed Int 16 bit G Force in 0 1G ...

Page 17: ...acklight mode The display will set the backlight to the dim setting if the ambient light is less then the threshold setting alternatively the display will set the backlight to the bright setting if the ambient light is greater then the threshold setting The ambient light received is shown as the ADC value in the top header Use this value to set the threshold value Security Setup Select this menu o...

Page 18: ...se during IFR in strument flight rules This implies that any such flight that uses the AHRS 4 SP X sensor packages as refer ence for either heading turn and bank or horizon is illegal 6 RS232 NMEA enabled GPS receiver message The AHRS 2 AHRS 4 and MAG 2 have the ability to be connected to a NMEA enabled RS232 GPS receiver to allow the AHRS 2 to use the actual ground speed in the attitude aiding al...

Page 19: ...instrument will then have to be returned to the factory Internal flash CRC error The instrument does a firmware check on the program when power is applied to the instrument If the program is corrupt in any way then the internal flash CRC error will be displayed Reload the instruments firmware and load default settings If the error message still persists then it could possibly be an internal flash ...

Page 20: ...and active satellites GPGSV GPS Satellites in view NMEA Supported Baud rate 1200 to 115200 10 Operating the alarms The alarm output can be used to switch an external alarm indicator The external alarm switch is an open collector tran sistor switch to ground with a maximum rating of 0 25A DC It is possible to wire the alarm contacts of several Stratomas ter instruments in parallel should this be de...

Page 21: ...o your aircrafts power supply Ensure that the supply voltage will not drop below 8V during operation as this may result in incorrect readings D15HD Pin Color Function 1 Red 8 30Vdc power via power switch circuit breaker and fuse 2 Black Ground 3 RS232 Transmit data Firmware upgrading 4 White Black Stripe RS232 Receive data Firmware upgrading NMEA GPS Input 12 Purple CAN Low 13 Pink CAN High 15 Whi...

Page 22: ...Blaze AHRS 2 AHRS 4 MAG 2 Operating Manual Page 22 13 Dimensions ...

Page 23: ...nd relevant pilot s license This person has to make themselves familiar with the operation of this instrument and the effect of any possible failure or malfunction Under no circumstances does the manufacturer condone usage of this instrument for IFR flights IMPORTANT NOTICE You must make your own determination if the products sold by MGL Avionics are safe and effective for your intended ap plicati...

Page 24: ...eter Airspeed ASI and Vertical Speed Indicator VSI EMS 2 Engine Monitoring System FF 5 Fuel Computer FLIGHT 3 Primary Flight Instrument INFO 2 Information Display G Force meter UTC and Local Time Slip Indicator Outside Air Temperature OAT Battery Voltage Current and charge display Flight Timer Flight Log Stopwatch Countdown Timer and Alarm MAG 2 Magnetic Compass Indicator MAP 4 Manifold Pressure a...

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