Title: DC Power Suppy Monitor
Post by: ezflyr on October 25, 2011, 08:28:10 pm
Post by: ezflyr on October 25, 2011, 08:28:10 pm
Hi All,
I just got the prototype boards back for my latest project, a DC power supply monitor with GLCD display! This power supply monitor is intended to measure the voltage and current of a DC power supply, and continuously display these values on a 128X64 pixel LED backlit GLCD display. A PIC 16F876A micro will be the "brains" of this project. Some unique features of the design include a switch mode power supply for inputs up to 30V, and an on-board 4.096V reference.
This project will be used with a commercially available power supply made by the Astron Corp. that is used as a ground power supply (GPU) for a general aviation aircraft. The power supply is used to operate the airplanes electrical system when the plane is on the ground undergoing tests. Monitoring system voltage and supplied current is important in this application.
The power supply voltage is scaled for the A/D input by a solder-selectable jumper (12V or 24V), while current is measured by an off-board Honeywell hall effect sensor.
I've got most of the firmware written for this project using a hand-wired prototype as a test-bed, so now it's time to build the real thing, and see how it works! I'll post some assembly pictures, and pictures of the power supply monitor in operation once I have it complete.
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John
I just got the prototype boards back for my latest project, a DC power supply monitor with GLCD display! This power supply monitor is intended to measure the voltage and current of a DC power supply, and continuously display these values on a 128X64 pixel LED backlit GLCD display. A PIC 16F876A micro will be the "brains" of this project. Some unique features of the design include a switch mode power supply for inputs up to 30V, and an on-board 4.096V reference.
This project will be used with a commercially available power supply made by the Astron Corp. that is used as a ground power supply (GPU) for a general aviation aircraft. The power supply is used to operate the airplanes electrical system when the plane is on the ground undergoing tests. Monitoring system voltage and supplied current is important in this application.
The power supply voltage is scaled for the A/D input by a solder-selectable jumper (12V or 24V), while current is measured by an off-board Honeywell hall effect sensor.
I've got most of the firmware written for this project using a hand-wired prototype as a test-bed, so now it's time to build the real thing, and see how it works! I'll post some assembly pictures, and pictures of the power supply monitor in operation once I have it complete.
[attachment=0]
John
Title: Re: DC Power Suppy Monitor
Post by: tayken on October 25, 2011, 08:30:20 pm
Post by: tayken on October 25, 2011, 08:30:20 pm
Interesting. Any schematics? Can you also take pictures of aircraft that are undergoing tests?
Title: Re: DC Power Suppy Monitor
Post by: ezflyr on October 25, 2011, 09:53:46 pm
Post by: ezflyr on October 25, 2011, 09:53:46 pm
Hi All,
I'll post the schematic and board files as soon as I've had a chance to check the functionality of the board. The design was done in Eagle, so it should be readily readable for anyone that is interested!
Here is a picture of the airplane this project is being designed to support. The GPU power supply will allow the avionics to be run on the ground for general testing, and database updating. The GPU will also power the electrically operated flap and landing gear systems while they undergo periodic testing. The airplane in question is a Beechcraft A36 Bonanza.
[attachment=0]
Thanks,
John
I'll post the schematic and board files as soon as I've had a chance to check the functionality of the board. The design was done in Eagle, so it should be readily readable for anyone that is interested!
Here is a picture of the airplane this project is being designed to support. The GPU power supply will allow the avionics to be run on the ground for general testing, and database updating. The GPU will also power the electrically operated flap and landing gear systems while they undergo periodic testing. The airplane in question is a Beechcraft A36 Bonanza.
[attachment=0]
Thanks,
John
Title: Re: DC Power Suppy Monitor
Post by: ezflyr on November 08, 2011, 02:32:57 pm
Post by: ezflyr on November 08, 2011, 02:32:57 pm
Hi All,
To update you on this project, I just finished populating the PCB, and so far all my hardware tests are looking good! I've got some test firmware running to exercise the display, and to check the analog inputs. One concern I had during the design was switching noise that might be generated by the on-board switching regulator, but early tests with an oscilloscope, and an analysis of the A/D converter readings leads me to believe this will not be an issue. I went with the switching regulator because the board can be powered at up to about 30V, and that was too much (power dissipation!) for the more familiar linear regulators I normally use!
[attachment=0]
Next up will be writing the final firmware, and incorporating any necessary calibration correction code to ensure accurate readings! I'm still missing one op-amp for the hall effect current sensing, but I should still be able to proceed with the firmware while I await its arrival!
Once this project is more or less 'complete', I'll post the Eagle schematic and board files as well as the firmware.
Thanks,
John
To update you on this project, I just finished populating the PCB, and so far all my hardware tests are looking good! I've got some test firmware running to exercise the display, and to check the analog inputs. One concern I had during the design was switching noise that might be generated by the on-board switching regulator, but early tests with an oscilloscope, and an analysis of the A/D converter readings leads me to believe this will not be an issue. I went with the switching regulator because the board can be powered at up to about 30V, and that was too much (power dissipation!) for the more familiar linear regulators I normally use!
[attachment=0]
Next up will be writing the final firmware, and incorporating any necessary calibration correction code to ensure accurate readings! I'm still missing one op-amp for the hall effect current sensing, but I should still be able to proceed with the firmware while I await its arrival!
Once this project is more or less 'complete', I'll post the Eagle schematic and board files as well as the firmware.
Thanks,
John