2019-04-26, 09:46 PM
New Heating Element
Fire in the hole!
NOTE: The following entry is around two weeks old. I just got around to annotating/cropping/compressing the photos for it.
So, as mentioned, my previous entry had an error in it, which I will correct in this entry.
I did not get to work on the OneUp at Build Night. Heck, I did not even get my car fixed, but I did a lot of work on it (the car, not the OneUp).
Anyway, working overtime, and just general hubris (is that the correct word?) kept me from messing with the OneUp directly. I had been looking at the Marlin firmware files, and I noticed that I had set TEMP_SENSOR_0 back to 1 (100K) at some point. This made no sense to me, as I needed it to be 0 (not used) in order to test the motors.
So, I finally started messing with the OneUp. The heating element and the temperture sensor were both disconnected from the RAMPS 1.4 board, which was fine as I was replacing them anyway. My first hurdle was the fact that in order to take up slack in these beasties I coiled the wires and used steel safety/lock wire as a sort of twist tie to keep the coils together. For those not familiar with safety/lock wire, you use special safety wire pliers to twist them, and then you do NOT un-twist them. The steel is too strong. That is why it is called "lock" wire.
I was, however, able to simply uncoil the heating element by sliding its bare wires out of the safety wire wrap. This gave enough slack/play within the rigid wrap to slide out the tempeature sensor's wire, with its plug.
Which brings me to a future hurdle: The new temperature sensors do not have plugs, so I will have to cut the plug off the old sensor, and solder it to the new sensor. The lack of a plug, however, made it easy for me to slip the wires back in the steel twist tie, along with the new heater wires, and coil both up nice and neat just like their predesessors.
I like the new heating elements in that the leads are semi-stripped. The insulation is cut but not removed. I removed the insulation, twisted up the strands and stuck them into the screw leads on the RAMPS board, and tightened down the screws.
Time for the correction: Remember how I said that I never built the special resistor test plug? Remember how I mentioned that the firmware was set back to a 100k sensor? Well, I was considering plugging the old sensor in, when I discovered a 100K resistor plugged in to the the RAMPS board. I *DID* build the resistor plug! Now it all comes back to my failing memory. My buddy Jack (not Jake, he's the Boy Wonder) brought in some old electronic odds and ends for me, which included something with the plug (which we cut off) and something that had a 100K resistor in it (which we removed, and soldered and shrink-wrapped to the plug).
I immediately fired everything up to see how it would work. Sure enough, no errors. Repetier-Host reported temperature at a constant, non-changing 24.4 degrees C. Just what one would expect from a constant, non-changing resistor.
But still, no heat. Not even from the new heating element. I fumbled around in the software, until I found a button labelled "heat extruder." Once I clicked this, the heating element immediately started generating heat.
At this point, I shut everything down, and declared another victory.
But, you don't get away from this story without learning something that I learned reading through the comments in Marlin's configuration.h file:
Tip: The 100K resistor plug is completely useless. Setting TEMP_SENSOR_0 to 998 or 999 does the exact same thing. It simulates a temperature sensor at a constant reading (that is configured elsewhere in configuration.h). All the same warnings that I made about the 100K resistor plug apply here. It is not for actual printing. It can cause fire, damage, death, etc. It is not giving an actual reading as to what is happening out on your print head, so RAMPS may overheat the head, or do something stupid based on misinformation. It is for testing your motors and extruder control only.
Been working overtime shifts, so do not know when I will get a chance to work more on this. Stay tuned.
Fire in the hole!
NOTE: The following entry is around two weeks old. I just got around to annotating/cropping/compressing the photos for it.
So, as mentioned, my previous entry had an error in it, which I will correct in this entry.
I did not get to work on the OneUp at Build Night. Heck, I did not even get my car fixed, but I did a lot of work on it (the car, not the OneUp).
Anyway, working overtime, and just general hubris (is that the correct word?) kept me from messing with the OneUp directly. I had been looking at the Marlin firmware files, and I noticed that I had set TEMP_SENSOR_0 back to 1 (100K) at some point. This made no sense to me, as I needed it to be 0 (not used) in order to test the motors.
So, I finally started messing with the OneUp. The heating element and the temperture sensor were both disconnected from the RAMPS 1.4 board, which was fine as I was replacing them anyway. My first hurdle was the fact that in order to take up slack in these beasties I coiled the wires and used steel safety/lock wire as a sort of twist tie to keep the coils together. For those not familiar with safety/lock wire, you use special safety wire pliers to twist them, and then you do NOT un-twist them. The steel is too strong. That is why it is called "lock" wire.
I was, however, able to simply uncoil the heating element by sliding its bare wires out of the safety wire wrap. This gave enough slack/play within the rigid wrap to slide out the tempeature sensor's wire, with its plug.
Which brings me to a future hurdle: The new temperature sensors do not have plugs, so I will have to cut the plug off the old sensor, and solder it to the new sensor. The lack of a plug, however, made it easy for me to slip the wires back in the steel twist tie, along with the new heater wires, and coil both up nice and neat just like their predesessors.
I like the new heating elements in that the leads are semi-stripped. The insulation is cut but not removed. I removed the insulation, twisted up the strands and stuck them into the screw leads on the RAMPS board, and tightened down the screws.
Time for the correction: Remember how I said that I never built the special resistor test plug? Remember how I mentioned that the firmware was set back to a 100k sensor? Well, I was considering plugging the old sensor in, when I discovered a 100K resistor plugged in to the the RAMPS board. I *DID* build the resistor plug! Now it all comes back to my failing memory. My buddy Jack (not Jake, he's the Boy Wonder) brought in some old electronic odds and ends for me, which included something with the plug (which we cut off) and something that had a 100K resistor in it (which we removed, and soldered and shrink-wrapped to the plug).
I immediately fired everything up to see how it would work. Sure enough, no errors. Repetier-Host reported temperature at a constant, non-changing 24.4 degrees C. Just what one would expect from a constant, non-changing resistor.
But still, no heat. Not even from the new heating element. I fumbled around in the software, until I found a button labelled "heat extruder." Once I clicked this, the heating element immediately started generating heat.
At this point, I shut everything down, and declared another victory.
But, you don't get away from this story without learning something that I learned reading through the comments in Marlin's configuration.h file:
Tip: The 100K resistor plug is completely useless. Setting TEMP_SENSOR_0 to 998 or 999 does the exact same thing. It simulates a temperature sensor at a constant reading (that is configured elsewhere in configuration.h). All the same warnings that I made about the 100K resistor plug apply here. It is not for actual printing. It can cause fire, damage, death, etc. It is not giving an actual reading as to what is happening out on your print head, so RAMPS may overheat the head, or do something stupid based on misinformation. It is for testing your motors and extruder control only.
Been working overtime shifts, so do not know when I will get a chance to work more on this. Stay tuned.
![[Image: avatar_23.png?dateline=1515658171]](https://fabric8r.com/community/uploads/avatars/avatar_23.png?dateline=1515658171){kind=avatar}