camrynekai Posted July 29, 2015 Report Share Posted July 29, 2015 (edited) Have had several emails in regards to how I modified my LEE Pot Temp Control. Here is the info needed. http://www.ebay.com/itm/Dual-F-C-Thermostat-PIDTemperature-Controller-TA8-SNR-K-thermocouple-80A-SSR-/291314464213?hash=item43d3b1f5d5 I also recommend to remove/bypass the stock Lee Temp control and you MUST preform a PID auto tune! Edited July 29, 2015 by camrynekai 1 Quote Link to comment Share on other sites More sharing options...
bryanmc Posted July 29, 2015 Report Share Posted July 29, 2015 (edited) Is the K sensor in contact with the actual heating element, with the crucible or just in the air space between the crucible and the outer housing? Edited July 29, 2015 by bryanmc Quote Link to comment Share on other sites More sharing options...
camrynekai Posted July 29, 2015 Author Report Share Posted July 29, 2015 Is the K sensor in contact with the actual heating element, with the crucible or just in the air space between the crucible and the outer housing? It is touching the bottom of the pot. The K sensor is located approximately 1" from the outside edge of the of the outer shell. The perforated holes around the K sensor is a MUST for accurate operation. 1 Quote Link to comment Share on other sites More sharing options...
mark poulson Posted July 30, 2015 Report Share Posted July 30, 2015 Cam, Do you heat the raw plastic in the Lee pots, or do you use something else, and just pour it into the pots once it's already kicked over? Quote Link to comment Share on other sites More sharing options...
camrynekai Posted July 31, 2015 Author Report Share Posted July 31, 2015 At the present time I just pour in raw plastic....with the lee lead model that i am using it gets hot quickly. From raw plastic to filled molds is taking just under 20 minutes. 5-7 of the minutes are being wasted waiting for my plastic to cool down and hit its pouring temp. 1 Quote Link to comment Share on other sites More sharing options...
Jaw Posted August 1, 2015 Report Share Posted August 1, 2015 Are you programming the controller as a pi or a pid controller? Derivative in the controller could be causing your 7min temp overshoot by anticipating a process upset that happened during the initialization of the first run I've always had better results when I eliminate the derivative control and just use proportional and integral(reset) but just a suggestion. Also is there room to install a thermowell to place the thermocouple in or is the bottom of the pot to shallow. Just curious might be a project I'm interested in trying in the future Quote Link to comment Share on other sites More sharing options...
mark poulson Posted August 1, 2015 Report Share Posted August 1, 2015 Are you programming the controller as a pi or a pid controller? Derivative in the controller could be causing your 7min temp overshoot by anticipating a process upset that happened during the initialization of the first run I've always had better results when I eliminate the derivative control and just use proportional and integral(reset) but just a suggestion. Also is there room to install a thermowell to place the thermocouple in or is the bottom of the pot to shallow. Just curious might be a project I'm interested in trying in the future Man, I wish there was a translation button on this forum! Quote Link to comment Share on other sites More sharing options...
Frank Posted August 1, 2015 Report Share Posted August 1, 2015 Sounds to me he is getting his temp up to get the plastic to a stable state and reducing it to a more pourable temp. Some plastics I guess need to get to 350 deg to stabilize the process. So don't think there is a fix in the electronics as it is just a procedure. One note on the PIDs you will find many many choices but most of the less expensive ones only display Celsius and not ferenheight so buyer beware of a good deal. Not that they won't work just have to convert. 1 Quote Link to comment Share on other sites More sharing options...
Jaw Posted August 2, 2015 Report Share Posted August 2, 2015 Ok I misunderstood I thought his controller was overshooting his disired temp and it was taking seven min to get back to a decent pouring temp. Seven minutes doesn't sound like much until you have to repeat it over and over. Sorry Mark after I posted that it came to me that maybe camrynekai May not be familiar with what I was referring to and was only following directions that came with the controller but I decided to leave the post just in case it could help. P. I. D. Controllers P stands for proportional (basically the amount of correctional action that the controller will take to correct a process variance) I stands for intergral or reset (usually expressed in minutes per repeat or repeats per minute that the corrective action will be applied) D stands for derivative ( acts kind of like electronic esp where the controller tries to predict a process upset based on the actions the controller has taken in the past) 1 Quote Link to comment Share on other sites More sharing options...
Jaw Posted August 2, 2015 Report Share Posted August 2, 2015 As for the thermowell it's just a solid tube that the k (type k thermocouple) could be threaded into and usually gives more of a uniform temp reading without directly contacting the substance (plastic) being monitored. I only asked because I'm not sure how thick the bottom of the pouring pot is and this also could eliminate the need for the holes around the sensor 1 Quote Link to comment Share on other sites More sharing options...
mark poulson Posted August 3, 2015 Report Share Posted August 3, 2015 Jaw, thanks for the explanation. Quote Link to comment Share on other sites More sharing options...
bryanmc Posted August 3, 2015 Report Share Posted August 3, 2015 The perforated holes around the K sensor is a MUST for accurate operation. Why is that? Quote Link to comment Share on other sites More sharing options...
Jaw Posted August 3, 2015 Report Share Posted August 3, 2015 I assume it's to disappate heat so the ambient temp around the sensor drops quicker instead of slowly cooling down but I may be wrong 1 Quote Link to comment Share on other sites More sharing options...
camrynekai Posted August 4, 2015 Author Report Share Posted August 4, 2015 Are you programming the controller as a pi or a pid controller? Derivative in the controller could be causing your 7min temp overshoot by anticipating a process upset that happened during the initialization of the first run I've always had better results when I eliminate the derivative control and just use proportional and integral(reset) but just a suggestion. Also is there room to install a thermowell to place the thermocouple in or is the bottom of the pot to shallow. Just curious might be a project I'm interested in trying in the future Ran in PID Format....I dont have an over shoot problem??? My Pouring temp is a long ways down from my kick temp. That is the reason I have to wait. Quote Link to comment Share on other sites More sharing options...
camrynekai Posted August 4, 2015 Author Report Share Posted August 4, 2015 Why is that? The trapped heat from the heating element would give you false readings....adding the vent holes around the sensor eliminated the anomaly. A well for the sensor would be great....but that puts this mod out of the reach for most DIYers. 1 Quote Link to comment Share on other sites More sharing options...
camrynekai Posted August 4, 2015 Author Report Share Posted August 4, 2015 Reason I use the TA8-SNR is the auto tune is spot on(no need for a degree in P.I.D. programing). Basically you fill your pots with plastic, turn on mixer, put the TA8 into auto tune mode and set a desired working temp (330ish) the unit then will take over and it will heat and cool your plastic in a 3 cycle format....after it does this you controller WILL work perfect +or- 2 degrees with NO overshoot. The settings will automatically be saved so this is a one time needed alignment. After your alignment is done you use the PID just like the digital thermostat on the wall of your home. Just a note....use junk plastic for this alignment because it WILL burn during this process. 1 Quote Link to comment Share on other sites More sharing options...
Jaw Posted August 4, 2015 Report Share Posted August 4, 2015 Ok I'm not that familiar with the pouring temps of soft plastics but I understand now that you are heating the plastic to a desired temp higher than what you pour. I work with a lot of different pid controllers and they all have different quirks glad you found a model that is easy to autotune Quote Link to comment Share on other sites More sharing options...
