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Difference between revisions of "DOA AnOut1"

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= Analog Outputs =
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= DOA_AnOut1 =
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== Uses ==
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Analog outputs can be used for
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*d'Arsonval movements (meter movements, eg used in analog multimeters)
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*dimmable Lamps
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*speed controllers, eg for fans (avionics cooling comes to mind :)
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*valves
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*other actuators
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*speakers (eg. used in CD players and MP3 players) and others
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In connection with a modulation scheme, it can be used eg. to control air-core instruments (like those found on a car dashboard).
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== Ways to generate an analog voltage from a digital signal ==
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*PWM, Pulse Width Modulation (this is the method discussed here and used by PHCC)
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*R2R Ladder, basically a bunch of (precision) resistors connected together in a way that looks like a ladder. Built from Resistors of two values, R and 2R (ie twice the value of the first).
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For more detals see the [http://www.allaboutcircuits.com/vol_4/chpt_13/1.html DAC section on allaboutcircuits.com]
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== PWM generated analog voltages ==
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In most cases, when Digital-to-Analog is required, PWM (pulse width modulation) can be used as the method to generate these voltages.
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PWM is usually the cheapest and easiest method for this. However, PWM is still only 0 Volts or it is 5Volts (for TTL level logic). The key is to calculate the average voltage of the PWM pulse. Often there is a low pass filter between the PWM output pin and the analog out terminal. This low pass filter "smoothes" the signal so it looks more like a real analog voltage than a bunch of HIGH/LOW pulses.
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Nowadays, PWM is used for many purposes, here are just a few:
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*switched power supply
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*speed control of several different kinds of motors, DC, AC, three-phase
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*stepping motors: current limiting, speed control, and microstepping
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*servo control
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*battery charging
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*brightness control for lamps and LEDs
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*and others
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=== Available or planned PHCC Analog Out Daughterboards ===
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==== DOA_AnOut1 ====
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'''Features:'''
 
'''Features:'''
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*software controllable refresh rate (usually called "PWM period")
 
*software controllable refresh rate (usually called "PWM period")
  
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==== Schematic and Layout ====
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== Schematic and Layout ==
  
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===== Rev.0B =====
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=== Rev.0B ===
 
[[Image:PHCC_DOA_AnOut1_sch.png|thumb|center|500px|Rev.0B Schematic]]<BR>
 
[[Image:PHCC_DOA_AnOut1_sch.png|thumb|center|500px|Rev.0B Schematic]]<BR>
 
[[Image:PHCC_DOA_AnOut1_brd.png|thumb|center|500px|Rev.0B Layout]]<BR>
 
[[Image:PHCC_DOA_AnOut1_brd.png|thumb|center|500px|Rev.0B Layout]]<BR>
  
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===== Rev.0C =====
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=== Rev.0C ===
 
[[Image:PHCC_DOA_AnOut1_rev0c_sch.png|thumb|center|500px|Rev.0C Schematic]]<BR>
 
[[Image:PHCC_DOA_AnOut1_rev0c_sch.png|thumb|center|500px|Rev.0C Schematic]]<BR>
 
[[Image:PHCC_DOA_AnOut1_rev0c_brd.png|thumb|center|500px|Rev.0C Layout]]<BR>
 
[[Image:PHCC_DOA_AnOut1_rev0c_brd.png|thumb|center|500px|Rev.0C Layout]]<BR>
  
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==== Assembly Instructions ====
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== Assembly Instructions ==
  
 
Formats available:
 
Formats available:
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*PDF version: [http://cockpit.varxec.net/electronics/phcc/tutorials/AnOut1_assembly_tutorial.pdf AnOut1_assembly_tutorial.pdf]
 
*PDF version: [http://cockpit.varxec.net/electronics/phcc/tutorials/AnOut1_assembly_tutorial.pdf AnOut1_assembly_tutorial.pdf]
  
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==== Bill of Materials ====
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== Bill of Materials ==
  
 
see [http://cockpit.varxec.net/electronics/phcc/download.html#DOA_AnOut1 download page].
 
see [http://cockpit.varxec.net/electronics/phcc/download.html#DOA_AnOut1 download page].
  
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==== Eagle and Gerber files ====
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== Eagle and Gerber files ==
  
 
see [http://cockpit.varxec.net/electronics/phcc/download.html#DOA_AnOut1 download page].
 
see [http://cockpit.varxec.net/electronics/phcc/download.html#DOA_AnOut1 download page].
  
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==== Changes between Revisions: ====
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== Changes between Revisions: ==
  
 
{| cellpadding="5" class="plain"
 
{| cellpadding="5" class="plain"

Revision as of 04:26, 13 November 2008

DOA_AnOut1

Features:

  • 16 channels
  • 8 bit resolution
  • uses DOA protocol
  • primarily for d'Arsonval type of instruments
  • other light loads can also be controlled with the built-in transistor outputs, eg to control cooling fan speed or dimmable lamps.
  • open collector outputs, max 45V (or more, depending on transistor)
  • software controllable refresh rate (usually called "PWM period")

Schematic and Layout

Rev.0B

Rev.0B Schematic

Rev.0B Layout

Rev.0C

Rev.0C Schematic

Rev.0C Layout

Assembly Instructions

Formats available:

Bill of Materials

see download page.

Eagle and Gerber files

see download page.

Changes between Revisions:

Rev.0C No functional changes. The outputs now feature a connector with more pins. The pinout on this connector thus changed. The odd-numbered pins all carry +5V, while the signals are on the even-numbered pins. Also added one capacitor, C2. Capacitor numbering changed as well.
Rev.0B First public release.
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