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Post by airtripper on Dec 30, 2012 13:24:34 GMT -5
This is good news because this explains why you get a reading without the thermistor plugged in I think.
Pins A13, A14 and A15 on the mega board samples the voltage coming from the resister/thermistor voltage divider at pins T0, T1 and T2.
The 5v supply is routed through the resistor, then through the T0 connector and then to pin A13. You have already measured 5v at the resistor for T0 so the problem area could be between the resister and the T0 connector. Use the schematic to identify the trace between the resistor and T0 connector.
Measure the voltage on both sides of the resistor For T0. If the voltage on one side of the resistor is as low as that on pin A13 then the resistor may be faulty and need replacing. If the voltage is normal then you need to check that the T0 pins are not shorted together causing the the 5V to short to ground.
But first, measure for 5v on the T0 pin again while pressing a finger or something onto the resistor on the same trace to rule out loose solder connection on the resistor leg. Testing the resistor with the multimeter probe could be making a temporary connection across a badly soldered joint giving a false reading.
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Post by airtripper on Dec 29, 2012 18:32:47 GMT -5
Using the same ground point, use the multimeter to measure each thermistor pin connector. One pin on each thermistor connector should measure 5 Volt while the is 0 volts. Then measure the pins on the ramps board that plug into A13, A14 and A15 on the mega board, which should be 5 Volts. You may have to separate the boards to note the pin labels on the mega board. Or you could use the guide image of the mega board below. If the voltages are correct, with the mega board plugged into the usb socket, start Pronterface and check the temperatures. They should read 0 at this point. If you get 0 degrees, power down, connect the thermistor to T0, power up and check the temperature in Ponterface again. We are looking for ambient temperature here. Hopefully you'll report back with a good result. Attachments:
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Post by airtripper on Dec 29, 2012 16:21:07 GMT -5
Looks like there might be a couple of solder bridges that should not be there, including the you spotted earlier (circled in red). Also, it looks like you have some poor solder connections like those circled in blue. The soldering looks a bit untidy and there should be no solder bridges like those circled in red. Where the blue circle is there are 3 resistors that form part of the voltage divider when the thermistors are connected. When the thermistors are not connected, you should be getting 5 volts across each resister. Remove everything from the ramps board and connect it to the mega board and apply power from usb and carefully measure the voltage across the resistors. Use one of the AUX connector ground (GND pins) to ground the multimeter. Attachments:
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Post by airtripper on Dec 29, 2012 13:38:45 GMT -5
Can you post an image of your board? so that we can see the soldering.
Mark
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Post by airtripper on Dec 27, 2012 18:10:01 GMT -5
I've just noticed the thermistor socket labels start with T0 and not with T1 as I thought before. I would start with looking at the traces, with a magnifying glass, for the thermistor first before doing any de-soldering. To check continuity you just put the probes on to spots that you think should be connected together or that you think should not be connected together. When using the continuity test feature on my multimeter I get a sound from the speaker whenever the two probes are connected via a circuit or solder joint. If I put a probe on each of the two pins for T0 on the Ramps board, I should not get a sound. If I do get a sound then there must be a short circuit that need to be found. On this reprap wiki page there are ramps images to help you with tracing the traces reprap.org/wiki/RAMPS_1.3Attachments:
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Post by airtripper on Dec 27, 2012 14:01:12 GMT -5
With no thermistor connected you should be getting 0 reading for both T1 and T2.
Your Arduino Mega must be picking up some kind of resistance on your Ramps board to get a resistance measurement for T1 and T2.
Because there is no thermistors connected, it would suggest that there is an electrical short on the Ramps board.
The next step is to examine the Ramps board, check that the solder is not connecting traces it shouldn't.
You could use a continuity tester to check that neighboring pins are not connected on the Ramps board.
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Post by airtripper on Dec 27, 2012 13:01:30 GMT -5
Ok, what readings do you get with no thermistor plugged into the ramps board at all?
Use the following settings so we can get readings from T1 and T2, but without any thermistor connected.
#define TEMP_SENSOR_0 1 #define TEMP_SENSOR_1 1 #define TEMP_SENSOR_2 0 #define TEMP_SENSOR_BED 1
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Post by airtripper on Dec 27, 2012 9:58:12 GMT -5
I think people use the baudrate that works best with their firmware and interface combination. If you are getting a temperature reading with no thermistor plugged in then you will need to check the ramps board for shorts. T2 will need to be switched on in firmware to get a reading. find the following code to edit: For T1 (Hot end only) #define TEMP_SENSOR_0 1 #define TEMP_SENSOR_1 0 #define TEMP_SENSOR_2 0 #define TEMP_SENSOR_BED 0 Put the hot end thermistor in to T2 and set the following code to read the thermistor as a heat bed temperature sensor. You may have to use Pronterface to check the bed temperature by ticking the check box at the top of the interface. For T2 #define TEMP_SENSOR_0 1 #define TEMP_SENSOR_1 1 #define TEMP_SENSOR_2 0 #define TEMP_SENSOR_BED 1 Note the readings for T1 and T2. Hopefully T2 will give something like room temp. Here is the reprap wiki on thermistor types reprap.org/wiki/ThermistorJust google each thermistor type to see what suppliers you get in your area.
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Post by airtripper on Dec 27, 2012 8:34:18 GMT -5
The steps per unit settings are at line 168, just change the 48.14 to 67.16.
The firmware baudrate is set to 250000, so set your 3d printer interface software (Pronterface/Printrun) to 250000 baud.
Your thermistor could be shorting, unplug the thermistor to the hot end and check the reading again. You should get 0 on the LCD panel.
It's a good idea to have a second thermistor for trouble shooting. Having a second thermistor means you can confirm two readings before you decide to pull apart the hot end to check wiring.
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Post by airtripper on Dec 26, 2012 20:51:08 GMT -5
Something I forgot to mention.
The config file is set to use the MK7 Drive gear and you may need to calibrate the extruder to fit the gear you are using on your printer.
If you are still using the original Sumpod drive gear, the settings below should work well enough. Just find the following lines in the config file to edit in 67.16.
//// Calibration variables // X, Y, Z, E steps per unit - Metric Prusa Mendel with Wade extruder: float axis_steps_per_unit[] = {106.76, 106.76, 800, 67.16};
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Post by airtripper on Dec 26, 2012 20:31:16 GMT -5
I've just checked and your version of Marlin is newer than mine and there is a lot of changes to the config file. I'll email you the version I'm using which would be quicker than me trying to work out the new changes in the latest config file.
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Post by airtripper on Dec 26, 2012 20:22:21 GMT -5
The config file is for Marlin V1 R2. I'll download Marlin again and verify and get back to you.
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Post by airtripper on Dec 26, 2012 18:56:49 GMT -5
I've attached the configuration file for download to use in Marlin firmware. Notes:Heated bed is not active. 100k thermistor is selected for hot end. 16x2 LCD is enabled. Z height will need checking for your printer. See the following for ref to edit the config file: #define X_MAX_LENGTH 130 // SUMPOD #define Y_MAX_LENGTH 130 // SUMPOD #define Z_MAX_LENGTH 90 // SUMPOD Stepper direction will need checking. Use Pronterface to check which direction the steppers are turning before attempting to home axis. Either correct the direction in the config file, or correct the direction by rotating the stepper motor connector on the ramps board. Remember to remove the power supply before doing so. Be ready to turn off the power when first attempting to home all axis to avoid crashing if any axis is going the wrong way. The settings in firmware will look like the following. Change to either true or false. #define INVERT_X_DIR true // for Mendel set to false, for Orca set to true #define INVERT_Y_DIR false // for Mendel set to true, for Orca set to false #define INVERT_Z_DIR true // for Mendel set to false, for Orca set to true #define INVERT_E0_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false Hope this helps, Mark Attachments:
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Post by airtripper on Dec 26, 2012 10:47:50 GMT -5
So that you can use the standard firmware basic setup, you should setup the hardware as per reprap wiki. Setup the Sumpod electronics to what is shown in the picture below. Then the only change to make is to plug the Z endstop into the Z+ connector instead of the Z- connector. Get Marlin from here github.com/ErikZalm/Marlin if you have not done so already, and I'll send you a config file soon. Full size version of the image: reprap.org/mediawiki/images/e/e3/Rampswire13.svg
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Post by airtripper on Dec 25, 2012 20:56:04 GMT -5
I've sent you a private message so you can email me your Sprinter config file.
I'll use that to configure the Marlin config file to send to you.
You can then use a file compare program like WinMerge to view the changes I've made against an unchanged version to see the difference.
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