EME - Antenna - Control - System:
|Short description of the features||
The system is based on a 89C51ED2 Microcontroller
Computation of position (without PC) of moon,sun,Cygnus,Sagittarius,Cassiopeia,Taurus,Leo and Aquarius
Demo - Version of the controller system
Digital position encoders you can get from http://www.usdigital.com . Look for the type A2-S-S, it has 0.1deg resolution and interfaces well to my system.
A much cheaper but probably less accurate solution is the MAB25 from Megatron with also 0.1deg resolution, it is discontinued now and replaced by the mechanically improved ETS25. Electrically it is the same as the MAB25:
Although the use of incremental encoders is not recommended, I programmed a 89C52 for converting the pulses to the SSI protocol. Get the firmware for it here: inc_ssi.hex See the circuit diagram in the controller documentation.
Andy Talbot, G4NJT, kindly developed hardware and firmware to interface a GPS module to the controller.
My azimut and elevation motors both do not need more than 1A for moving my 7.3m dish!
But there seem to be some systems around with more powerful motors, maybe for tracking a moon which is moving over the sky very quickly ;-)
Walter Crauwels, ON4BCB, has developed a nice modification using more powerful H-bridges which can handle up to 43A!! Look at: H_bridge_mod_ON4BCB
|-||Azimuth and elevation motor controlling for all targets plus two free choice positions|
|-||Transmission of antenna position via LAN cable from antenna down to the controller in the shack|
|-||Interfacing with different absolute encoders
is possible: 10..12bit
A2-S-S, MAB25, ....
|-||Selectable stepsize for tracking|
|-||Selectable offset for azimuth and elev. up to +/- 9.9 deg|
|-||Motor control output clw/ccw up/down, including soft-start and soft-stop|
|-||Local operation by 4 buttons at controller,
non volatile storage of all parameters
( remote operation by PC is possible)
|-||Real - Time - Clock|
|-||4 x 20 character LCD - display|
PC is not necessary for controlling (no interference!), single wire line from antenna (encoders) into shack, ready within a few seconds
HEX - FILE FOR CONTROLLER :
See a step by step guide how to upload the firmware, written by HB9DRI: AN02.pdf
19Oct16: Only difference of V7.8 to V7.6 is display of the new Megatron encoder ETS25 instead of MAB25.
Only difference of V7.8a to V7.7 is display of the new Megatron encoder ETS25 instead of MAB25.Using this feature, a hardware modification is necessary. See description below!
11Aug15: PWM speedcontrol in manual mode included.For using this feature, a hardware modification is necessary! Idea and description manual_speedcontrol.pdf by ON4BCB
30April15: problem with unstable readout when using the USdigital A2-S-S encoder fixed
22July14: Inclinometer ACS-360-1-S102-VE2-PM (Posital) for elevation, together with MAB25 for azimuth included
22Nov2013: version V74 (my individual solution)
25Aug13: Doppler shift calculation improved for better accuracy eme_contr_jfl_v73.hex
23Nov12: Doppler shift indication for 3.4GHz and 24GHz included, remote commands for antenna offset compensation added
20Oct12: new style of offset compensation included and interference from PWM to encoder reading fixed. Read the additional documentation, written by HB9DRI: AN03.pdf
BRD - FILES FOR PCBs :
DOC FILE WITH DETAILED DESCRIPTION:
AVAILABILITY OF CONTROLLER MODULES / PCBs
I will not provide myself PCBs or completely built modules, but kindly HB9DRI (member of HB9Q group) will do so.
Alex has written an additional very useful documentation how to test, install and interface the system to the antenna.