RAMPS 1.4 Low Vcc June 24, 2015 04:17PM |
Registered: 8 years ago Posts: 4 |
Re: RAMPS 1.4 Low Vcc June 24, 2015 04:33PM |
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Re: RAMPS 1.4 Low Vcc June 24, 2015 04:49PM |
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Re: RAMPS 1.4 Low Vcc June 24, 2015 05:37PM |
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Re: RAMPS 1.4 Low Vcc June 24, 2015 06:23PM |
Registered: 8 years ago Posts: 4 |
Quote
AndrewBCN
Exactly what Tim wrote, adding two small points:
1. What voltage are you supplying to the RAMPS? Did you leave the D1 diode in the RAMPS? Can you measure the voltage across D1 when printing (it should be something like 0.8V)? You see, the regulator on the Arduino will work fine if you supply it with something like 7 to 12V, and the D1 diode on the RAMPS is supposed to pass approximately 11.2V to the Arduino regulator. If you have > than 11.2V, you risk overloading the Arduino regulator. Also, if your PSU does not properly regulate the +12V output for some odd reason, again you could be overloading or underloading your Arduino's voltage regulator.
2. Under normal conditions, the RAMPS + LCD does not require more than 50mA to operate, and that is easily within range for the Arduino regulator. But if you have a servo or anything using > 50mA on the RAMPS VCC, the Arduino regulator may not keep up... simply because it's not designed to.
Re: RAMPS 1.4 Low Vcc June 24, 2015 06:27PM |
Registered: 8 years ago Posts: 4 |
Quote
Cefiar
Note: If you have an external 5V source (eg: a 5V line from a PC PSU), then you can supply RAMPS completely with this 5V source.
You need to:
1. Remove D1. This stops RAMPS supplying voltage to the on-board regulator.
2. Connect your 5V source to a 5V/VCC line on the RAMPS/Arduino. Note that there is a "second" 5V line that goes to the servos that ISN'T connected to the main 5V line by default.
Regarding the LCD comment: The issue usually is that while an LCD may only use 50mA itself, the backlight can in some cases use quite a bit more, and this causes real issues overloading the regulator.
As for RAMPS, the board covers the Arduino regulator area (preventing airflow), and the Arduino regulator is poorly laid out for efficiently disposing of excess heat. The upshot is that they can easily overheat even at 12V input and less than their rated current, due to something as simple as a bad solder joint (so the regulator doesn't lie flat on the PC or if the ambient temp is > 25 Deg C.