Temperatures do not update when Heatbed turns on

Hello RepRap Community,

I'm having issues with the USB Connection when the Heatbead turns on and would be very grateful if you could help me out.

First the specs of my Printer:

- Prusa I3 Frame from RepRapUniverse
- 400 Watt Micro-ATX Techsolo TPS 400 Power Supply (12V1 - 14A / 12V2 - 10A, Green Pwr_On Cable is Grounded)
- Ramps 1.4 on Arduino Mega 2560
- Heatbed MKII
- 100K Thermistor
- E3D V6 3mm Hotend

I'm building my Printer for 2 Weeks now so I'm still an absolute beginner.
The Printer is fully installed with all Motors succesfully tested.
So far I'm only using Pronterface via USB.

The Problem
When I turn on the Heated Bed in Pronterface both temperature readings (Hot End & Heated Bed) stop updating.
I can still use all functions of Pronterface like moving any axis or power up the hot end. Turning the power off (Hot End & Heated Bed) is also possible.
My device manager still shows the arduino as connected.
If I disconnect the connection via Pronterface I cannot reconnect it. (It says "Connecting..." in the Serial Monitor forever)

What I have found out
Even though it doesn't update the Temperatures the Ramps Board still shuts down the power of the Heatbed after the designated Temperature is reached.
The only way to reestablish the USB connection after a disconnect is to fully shut down the ATX PSU and cut off the USB connection.
I measured the voltage at the Ramps 12V Input and found out that if the Heatbed is powered it drops from ~12,4V to ~10.8V and recovers at ~11.0V.
I tried a bigger 700W ATX PSU with the same voltage drop.
If I power up the HotEnd only the Temperature updates just fine
After a full reconnect (OFF and On again) both Temperatures update as usual.

I don't even now if its harmless for printing since I haven't tried it yet (still waiting for replacement fan for the coldend) but I find it confusing and would like to keep control over the Temperatures.
Could you please help me what to do?
If you need and further Information please tell me!

Thank you very much for your help!

Edited 2 time(s). Last edit at 01/04/2015 08:30PM by Garfiled.

What version? There was an issue with older version, the new one corrects the temp reading issue. There is also a bata version, that has some new cool features.

Hey, thank you for the fast reply

I'm using the Printrun Package from 10.03.2014 and Marlin version 1.0.1.

The Configuration.h file from Marlin is attached

Edit:

Just found out via the debug option in pronterface that the printer stops sending the basic information as soon as I turn on the Heatbed
By accident I touched the mosfet for the Heatbed and it was smoking hot (burnt fingertip). I assume there is something wrong with the Heatbed (sucking to much amps?)
Unfortunately I can't measure the Amps drawn by the heatbed (I only have a cheap multimeter)
So it seems like a hardware problem...

Any Ideas what to do?

Edited 4 time(s). Last edit at 01/05/2015 09:20AM by Garfiled.

Hi Garf,

May I ask what setting did you use in you configuration file to indicate the Thermal Resistor.

I use Marlin firmware code with Arduino IDE.

We have an issue with temperature as our documentation is difficult to obtain information from.

The actual Thermal Resistor value code indicates the resistance and manufacturer. This value is entered into the firmware code.

We are using 8 for the heating bed, but can not determine the value for the extruder thermo resister.

z605 Aurora Prusa I3, Melzi 2.3 board, Repeiter host software

Thanks,

Nick

You need to put a load on the PSU_ON, not just ground it, that's probably why you're seeing such a large voltage drop when you power on the heatbed. Nophead also advocates a load on the 3.3v as well, although YMMV depending on model of PSU.

@Nick
Hi Nick,
The Thermistor on my E3D V6 Hotend says to be a 100k Ohm Semitec so I chose option 5 (the only Semitec with 100k). in my uploaded config.h its is mistakenly valued 1
The Thermistor from the Heatbed just says 100k without any specification so I chose option 1 since this is usually delivered with the MKII Heated Bed.
Which Hot End do you use?

@plankton
I will try that out, thanks for the advice! Is a small 5V fan enough or will I need a bigger load?


I ordered a 20A Multimeter to test if the Heated Bed is sucking to much or the ATX PSU is delivering to less amps.

Edited 2 time(s). Last edit at 01/05/2015 08:19PM by Garfiled.

Many people just use a 47 ohm resistor on the 5v rail, check the resistance of your fan, but I expect that will work.

This page on the Wiki explains the reasoning, I don't know if it's entirely true (as stated on that page) that recent ATX power supplies don't need any load on the 5v rail (it may just be that they suffer less from voltage drop).

Edited 1 time(s). Last edit at 01/06/2015 02:44AM by plankton.

HI Garfield,

thank you very much for the reply.

The system we purchased is the Aurora Z605 Prusi I3.

We can not find out in the documentation what we have for the hot end element and Thermal Resister.

The Parts List does not indicate specifics on the Hot End, which is the reason we are having difficultly.

We are using setting 8 in Marlin Configuration.h for the hot bed and the readings are within a few degrees of what the Repeter Host software indicates the temperature is on the Hot Bed.

We also tried each of the settings by trial and error, heated the extruder and could not get any temperature to be close.

I will keep trying the 100KOhm settings and the one you indicated you have.

The Kit did come with a spare thermal resister that had the following text on the heat shrink VW-1 HFT (030/1.5)

Thank you for the help and I greatly appreciate talking with you

NIck

Quote
nick001
HI Garfield,

thank you very much for the reply.

The system we purchased is the Aurora Z605 Prusi I3.

We can not find out in the documentation what we have for the hot end element and Thermal Resister.

The Parts List does not indicate specifics on the Hot End, which is the reason we are having difficultly.

We are using setting 8 in Marlin Configuration.h for the hot bed and the readings are within a few degrees of what the Repeter Host software indicates the temperature is on the Hot Bed.

We also tried each of the settings by trial and error, heated the extruder and could not get any temperature to be close.

I will keep trying the 100KOhm settings and the one you indicated you have.

The Kit did come with a spare thermal resister that had the following text on the heat shrink VW-1 HFT (030/1.5)

Thank you for the help and I greatly appreciate talking with you

NIck

That marking on the cable is for the cable not the Thermistor

Option 8 is definatly not for the hotend as 8 is a SMD device (possibly is correct for the heatbed as they can be directly soldered to the bed) I would try option 1 for a epcos as that seems to be the most common

If it is a original E3D V6 (Not a Chinese clone) then they come with a semitec thermistor which is 5 in Marlin

HTH

Doug

Problem Solved
Thank you very much guys!

I tried a 47Ohm Resistor on the 5V rail but it got unpleasantly hot.
So I hooked a 5V Servo to the rail and tried to power the Heatbed with success and remaining serial connection.
The crazy thing is that the voltage still drops to 10.76V when powering the heatbead but the serial connection doesn't break and the desired heat is achieved quickly.
When I get the multimeter I will post the Amps of my heatbed.

So if this helps someone with the same kit or ATX PSU:

To use a Techsolo TPS-400 Micro ATX Power PSU a load on the 5V rail need to be applied.

Thanks again


@nick
is this your printer?
If so the Hotend is a Koolertron 0.4 K-Type as you can see here.
This one uses a K-type Thermocouple which needs some more electronic to work.
I only found this but unfortunately it's in german.
But I'm sure there's an explanation how to deal with this in English as well.
Hope this helps

Edited 3 time(s). Last edit at 01/07/2015 12:13AM by Garfiled.

Hi Garfield,

Thank you for looking into this,

Our printer is very close to that, but with a different extruder.

The link below is our exact printer and you can see which extruder we have:

[www.amazon.com]

If you have any information on which one it is that would help.

Thanks to you and Dougal1957 for the help.

Best regards

Nick

@Nick:

Is this your Hotend?
It's still seems that your Hotend is equipped with a Thermocouple, which needs to be operated differently than Thermistors (It needs an Amplifier) see here
The Repetier Software seems to save all configurations inside the program itself instead of being defined in the marlin configuration.h (referring to this))
I'm sorry I can't help you out here but I suggest to just open a new thread with this problem.
You could also just write an E-Mail to your seller and describe him the problem (maybe you are not the only one with this issue).

I'll keep my fingers crossed that you find a solution!

hi garfield

just wanted to thank you and all for helping.

we are able to get temps in range and can print with abs.

next we are working on line tension and feed rates

best nick