1 Topic by insta

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Topic: Potential optimization (in testing)

Our PID controllers have an option for "alarm".  This is a function designed to trigger a relay, built into our units, when some programmed condition has occurred.

I decided to use this to run my motor.  I've set my "HIAL" setting to 155 in the settings.  That's all I had to change, and I set my temperature to 156C.  The motor is connected between pins 11 and 12 of the PID controller, instead of running through the switch.  Now, whenever my temperature climbs above 155C, the motor will automatically turn on.  This has allowed me to run switchless, using only the power cord to turn the entire unit on and off.  This will also save our butts if the heater band or relay fails and the temperature falls, while it's running overnight.  The motor will shut off and prevent damage.

Thoughts, ideas?  I don't want to take pictures yet, it's a little fugly on the wiring...

2 Reply by elmoret

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Re: Potential optimization (in testing)

Yup, been done before by myself and others. It's called autostart, or that's what I call it at least.

Filastruder - the robust, inexpensive filament extruder
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3 Reply by insta

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Re: Potential optimization (in testing)

Well that's what I get for trying to be clever.

4 Reply by elmoret

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Re: Potential optimization (in testing)

No, its good to be clever - keep it up!

It complicates the wiring a little and I was trying to keep things simple early on. I don't think it is good to run completely switchless, though I guess switchless autostart isn't much more complicated that what the wiring is right now. I'll look at incorporating it into the next revision of the instructions. It was actually there for a little while, then I got complaints about things being too difficult to understand. I'll have to figure out a way to clearly explain what it does and how to wire it.

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

5 Reply by insta

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Re: Potential optimization (in testing)

I actually got all the wiring for the whole machine done on the back of the timer.  Each screw terminal has about 2 wires.

My previous version had a full terminal strip, wire nuts, all that ... this seems to have cleared up the wiring a lot.

6 Reply by bubbasnow

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Re: Potential optimization (in testing)

its still probably good to have a switch in the circuit for troubleshooting or maintenance sake.  So all i would have to do is put the relay in the PID controller (pin 11/12) in series with motor switch set up in the current wiring configuration?  then leave the switch in the on position to let it auto run or in case i need to shut it off but leave heat going just flip it.

7 Reply by elmoret

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Re: Potential optimization (in testing)

Yup - that would do it.

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E3Dv6 All Metal Hotend - the premier 3D printing hotend

8 Reply by insta

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Re: Potential optimization (in testing)

That's also a much better idea than leaving it hooked up straight to "autorun".  The problem I had at first was I had my alarm temp set to 135C (was trying HDPE) and 135C was too cold to extrude.  So the whole machine starts groaning and twisting as I'm trying to get the hotend hotter before it destroys itself.

Of course the correct course of action after an event like that is to start a post ending with "(in testing)" so nobody is fully aware of the issues wink

9 Reply by bobnojio

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Re: Potential optimization (in testing)

admittedly I dont have my filastruder yet (only ordered it on Monday, and it shipped Friday!), but I would recommend (from theory)

Motor power:
from supply, through Motor on/off switch, to a relay, to the motor, back to the supply.

PID Alarm:   from the PID, to the control side of a relay.

This way, you still have the on/off function of a switch, and you could, in theory, disable the motor for either an initial warm-up hold or maintenance, but still having the PID alarm as a master switch to not break anything at the start (cold), or a temperature drop to temporarily stop the motor.

10 Reply by elmoret

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Re: Potential optimization (in testing)

PID alarm has an internal 5A relay so there's no need for one externally, otherwise what you say is correct.

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

11 Reply by bobnojio

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Re: Potential optimization (in testing)

ah.  the PIDs im used to have the alarm as a voltage source, not a relay.  that should make it even easier to do!

12 Reply by bobnojio (edited by bobnojio 2014-05-30 16:54:00)

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Re: Potential optimization (in testing)

finally had time to try and sketch out what I was talking about, using the PID high temp alarm for a switched auto-start / low temp cutoff for the motor/fan.


What I have done:
according to the datasheet for the Sestos PID Controller:
ALARM1:
pin12 is common
pin11 is Normally Open
Pin1 is Normally closed

for output:
pin7 is common
pin8 is Normally Open
Pin6 is Normally closed.


Changes:
moved Motor/Fan switch:  it now controls the +12 going to pin12 of the PID controller (COM for alarm)
Moved Motor/Fan:  these now wire into Pin 11 of the PID, (Normally Open for Alarm)
result:   as long as the motor/fan switch is ON, the PID alarm relay will only supply voltage to the motor and fan if the high-temp alarm (set by me) is active / alarming.
if the temperature drops below the alarm threshold, the PID relay will kill power to the motor and fan (low-temp cutoff)
**will have to make sure to set the PID high-temp alarm appropriately**

Moved heater from pin7 (COM) to pin8 (N/O)
personal preference...  I prefer my volage on the common and my load on NO/NC.  (no relevance to the discussion on PID autostart / cutoff.

Does anyone see any flaws in this concept?

i have to wait to get access to a dremel this weekend to prep my nipple, and will likely be wiring/extruding this coming week.

edit: just in case it didnt attach:  http://i.imgur.com/VnBqEFJ.png

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13 Reply by elmoret

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Re: Potential optimization (in testing)

Looks good to me!

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E3Dv6 All Metal Hotend - the premier 3D printing hotend

14 Reply by insta

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Re: Potential optimization (in testing)

bobnojio wrote:

i have to wait to get access to a dremel this weekend to prep my nipple


teehee