Heated Bed Won't Start Without Hotend Being On

Hello Everyone. I've got a v2 Mendel with RAMPS1.4 on an Arduino Mega with Marlin loaded on it. I've got what might be termed a mild annoyance, but I want to check and see if this might be a sign of something bad.

When I go to pre-heat my printer's bed with pronterface/printrun, it will not work unless I am also heating my print head. Here is exactly what I see in the pronterface output window:

Connecting...
start
Printer is now online.
echo: External Reset
Marlin 1.0.0 RC2
echo: Last Updated: 2012-31-10 | Author: brad
echo: Free Memory: 4507 PlannerBufferBytes: 1232
echo:Using Default settings:
echoD init fail
ok T:21.6 /0.0 B:22.4 /0.0 @:0
Setting bed temperature to 95.000000 degrees Celsius.
Error:0
: Extruder switched off. MINTEMP triggered !
Errorrinter stopped deu to errors. Fix the error and use M999 to restart!. (Temperature is reset. Set it before restarting)

So, my routine now is:
Turn on printer power.
Connect via pronterface.
Set hotend temperature to 225 (say)
Set heated bed temperature to 95 (say)
Set hotend temperature to 0.

This process works fine, but it is a little annoying in that it interferes with my ability to comprehend everything.

I'm kind of surprised and confused by the MINTEMP message, since my thermistors are registering the ambient temperature (21*C) and I have set these lines in Marlin:

#define HEATER_0_MINTEMP 5
#define HEATER_1_MINTEMP 5
#define HEATER_2_MINTEMP 5
#define BED_MINTEMP 5

Does anyone know what might be going on here?

Can we assume that you uploaded the firmware after changing the MINTEMP defines?
A stupid question I know, but you would be surprised how many times the answer to this question is - No!

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

rhmorrison Wrote:
-------------------------------------------------------
> Can we assume that you uploaded the firmware after
> changing the MINTEMP defines?

Yup. It's been compiled and uploaded numerous times for various tweaks and changes I've made. (New extruder gear ratios, new belt sizes, etc.) Given a choice, I'd opt for an easy answer with my failures at the center of it. But I'm losing hope that this is the case.

I should add that this problem I'm describing has been the case since day one with my board.

I was getting that error message, when I was testing my stepper drivers, bed,hotend & thermistors weren't connected.
(it's a new build, also my first build, so bear that in mind)

You can get rid of the error message by setting mintemps to -1 . Just try it with heater_1, see if it allows you to preheat the bed ?

Not a prob for me because those thing weren't connected, but in your case I would just use it as a quick test.

maybe look through rest of firmware for any instances of heater/bed defs make sure they're ok ?

That's a thought. Since I'm not worried about the heated bed getting too hot (at least in the same way that a too-hot extruder ruins itself) I might try just disabling the heated bed MINTEMP entirely.

Hi,

not sure setting bed MINTEMP will get rid of the error message since it specifically mentions hotend MINTEMP (extruder MINTEMP).

Had a bit more time this morning,so had a quick look through the thermal settings in the firmware.

Those MINTEMP's are for checking the functionality of your thermistors, to make sure they're working. Again for me
at the time its not an issue they weren't connected, in your case you should only change them for quick test, and not disable them permanently, they're important.

In the marlin I have from github, just below where you define your thermistor (TEMP_SENSOR_0 etc) in the firmware is this :

// This makes temp sensor 1 a redundant sensor for sensor 0. If the temperatures difference between these sensors is to high the print will be aborted.
//#define TEMP_SENSOR_1_AS_REDUNDANT
#define MAX_REDUNDANT_TEMP_SENSOR_DIFF 10

Above is what's defined as default in my firmware. I'm making a big assumption here, so could well be wrong, but as far
as I know there is only one thermistor on my hotend, assumed TEMP_SENSOR_0 which is set to 1 for 100k thermistor, TEMP_SENSOR_1 is set to 0, so therefore I would need to uncomment TEMP_SENSOR_1_AS_REDUNDANT and
comment MAX_REDUNDANT_TEMP_SENSOR_DIFF 10 ?

this could be what's throwing the error message ?

check your firmware see what's there by default. You may want to check the other thermal settings in the firmware to.

Edited 2 time(s). Last edit at 06/12/2013 04:32AM by Masnachu.

Thanks, Masnachu. That sounds like a promising lead. I'll peek inside, and see what I have.

None of this, though, explains why I get the error when I try to turn on the heated bed when the extruder is off, and why I don't get the error when the extruder is on. To my mind, if the problem was with Marlin defaults, everybody would have this problem. The answer is going to have to explain why I'm so special. I strongly suspect that I have a funky RAMPS board.

The idea of redundant thermistors appeals to me, too, but my j-head has the very nice hole for just one...

Edited 1 time(s). Last edit at 06/12/2013 11:16AM by Karmavore.

Deleted answer because it didn't explain why error doesn't occur when you set hotend temp.

I'll try and do some more thinking, don't hold your breath though


How are you setting the heatbed preheat ? through the pronterface interface (bottons & input box) or directly with M codes?

Edited 2 time(s). Last edit at 06/12/2013 03:55PM by Masnachu.

Masnachu Wrote:
-------------------------------------------------------
> How are you setting the heatbed preheat ? through
> the pronterface interface (bottons & input box) or
> directly with M codes?

Through the pronterface interface. (And within gcode created by Slic3r, of course.) I know I set it a couple times with M codes typed into Pronterface, but that was a while ago and I didn't do it often.

just uploaded a default firmware (just changed electronics board, TEMP_SENSOR_0 1 , TEMP_SENSOR_BED 1)

getting MINTEMP error, thing is I can set Heatbed temp on it own both with pronterface buttons and through M codes , and it does it with no further error codes etc (still haven't got any hardware connected to ramps)

Connecting...
start
Printer is now online.
echo: External Reset
Marlin 1.0.0
echo: Last Updated: Jun 12 2013 21:05:21 | Author: (none, default config)
Compiled: Jun 12 2013
echo: Free Memory: 5313 PlannerBufferBytes: 1232
echo:Hardcoded Default Settings Loaded
Error:0
: Extruder switched off. MINTEMP triggered !
Errorrinter stopped due to errors. Fix the error and use M999 to restart. (Temperature is reset. Set it after restarting)
Setting bed temperature to 110.000000 degrees Celsius. (<- me hitting the button)
>>>M105
SENDING:M105
ok T:0.0 /0.0 B:0.0 /0.0 @:0 B@:0



your getting "Setting bed temperature to 95.000000 degrees Celsius. " just before the mintemp error, is that being set in your firmware ? or from somewhere else ?

Masnachu Wrote:
-------------------------------------------------------
> your getting "Setting bed temperature to 95.000000
> degrees Celsius. " just before the mintemp error,
> is that being set in your firmware ? or from
> somewhere else ?

The 95 degrees is what I'm setting the bed to in Pronterface, and then hitting the "Set" button. It is not coded into the firmware.

One thing that shocked and amazed is that your Pronterface error doesn't have the "deu" typo in it. I don't think that my problem is a Pronterface/printerun issue, but I might as well upgrade. I haven't checked on it since I first installed it in October.

I've also looked into my Marlin code, and it appears to me, at least, that as long as I have EXTRUDERS defined to be 1, all the other MINTEMPS won't even get compiled in.

Karmavore Wrote:
-------------------------------------------------------
> Masnachu Wrote:
> --------------------------------------------------
>
> The 95 degrees is what I'm setting the bed to in
> Pronterface, and then hitting the "Set" button. It
> is not coded into the firmware.

Ah, so 'default settings loaded' is the last output from your firmware after it's booted
(thought last output was the mintemp error, as with mine)

> One thing that shocked and amazed is that your
> Pronterface error doesn't have the "deu" typo in
> it. I don't think that my problem is a
> Pronterface/printerun issue, but I might as well
> upgrade. I haven't checked on it since I first
> installed it in October.
>
> I've also looked into my Marlin code, and it
> appears to me, at least, that as long as I have
> EXTRUDERS defined to be 1, all the other MINTEMPS
> won't even get compiled in.

I only changed #define HEATER_0_MINTEMP to -1 today so I could test a replacement pololu driver, and that got rid of
the mintemp error and switching the printer off problem, so you could be right.

I threw a pair of thermistors into 2 empty header sockets, and run it with the same default firmware as last post, it lets me set bed temp with no errors.
-------------------------
Connecting...
start
Printer is now online.
echo: External Reset
Marlin 1.0.0
echo: Last Updated: Jun 13 2013 17:02:17 | Author: (none, default config)
Compiled: Jun 13 2013
echo: Free Memory: 5313 PlannerBufferBytes: 1232
echo:Hardcoded Default Settings Loaded

>>>M105 (me in pronterface)
SENDING:M105
ok T:20.0 /0.0 B:20.6 /0.0 @:0 B@:0
Setting bed temperature to 110.000000 degrees Celsius.
>>>M105
SENDING:M105
ok T:20.0 /0.0 B:20.0 /110.0 @:0 B@:128

----------------

if upgrading pronterface doesn't change anything, maybe try downloading the firmware again into a temp directory (just to cross it off the list as a possible cause if nothing else). Just change the minimal stuff (as in my last post) and see if you still get the error. All that would be left then is RAMPS.

Edit: just noticed "Marlin 1.0.0 RC2" in your first post, so looks to be a different firmware from mine ( Which I got from here)

Edited 1 time(s). Last edit at 06/13/2013 12:58PM by Masnachu.

Hold all your calls, folks, we have a winner!

I got the latest version of the Marlin firmware. No change.
I got the latest version of printrun. Fixed!

So the problem was somewhere in old printrun or some combination of old printrun and old Marlin. And I very much like how this new version of Pronterface is showing me a much smarter "time until finish" number.

Thanks Masnachu, for your keen eye going over the logs.

Bad News/Good News update.

It wasn't fixed, at least not totally. For whatever reason, the hotend didn't need to be as hot for the heated bed to start, but it did have to be just a hair warmer than ambient. Marin/Printrun wasn't the issue.

It turns out, and I'm not surprised by this, that the issue was a loose or possibly entirely disconnected ground wire coming from the power supply into RAMPS. Now that it is addressed, I can start my heated bed first thing. It also gets to temperature much faster.

Thanks again everyone, and the final answer is: loose or disconnected ground into RAMPS from the power supply.