Tried running the new Solder Pot Controller code for the SLED-C4 Display today with no luck. Display only shows ths 8888 default splash screen. I have checked all the wiring connections several times and they are all correct. Maybe I don't understand how the encoder works or maybe it's a bad BS2P-24 chip. What am I doing wrong ? Help....
Well, on the display pin 3 must be connected to pin 5 for 9600 bps. Be sure you have the pins in the correct order and connected to the pins as shown in the code. The code I posted initializes the displays 3rd decimal point so you should at least see that. Oh wait! I know…You are using the BS2p and sicne I damaged mine I was using a BS2px…The baud rate value is incorrect and is for a BS2px. Change the baud rate value from 396 to 240. Sorry about that! Nothing else should need to change. Let me know how it works out for you.
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That did it, But I can only go up to 120 when setting the temp set point. Also the heat LED no longer works. I think that I have a bad chip because when running the old code, the LED did work but had a intermittent flash. I have re-seated the chip but the Led is still not working....
The reason you can only go to 120 is because that is the value set in the code. You could change the range to whatever you want. In the final code I will make these constants so it is easier to see/pick out. What range would you like in this code? Also the LED could easily be assigned to another I/O pin by just changing the PIN declaration in the beginning of the code.
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Ok, I will re-set the range and try another pin. For some reason the Led is back on but it will not go off when applying heat to the thermocouple wire when the set point is at 120. Also the chip locks up after being on a short time. By locking up I mean that I can't re-set the Temp set point during this lock up period. To get it to work again I must turn the power off and back on again. Bad Chip ?
Re-set the temperature operating range and re-assigned the led to another I/0 pin and all is working ok now, with the exception of when applying heat to the thermocouple lead. The led will not turn off at any temperature set point.
Interesting…Okay, so what are you setting the Set Temp to and what is the display reading when you apply heat to the thermocouple probe? Upon startup, as soon as the current temperature is equal to or exceeds the Set Temp the unit should beep three times and the LED should go out until the temperature drops again below Set Temp. To change the pin assignment for the LED all you would have needed to do was change LED from 14 to whatever new pin you wanted. The fact that it is on indicates it should be working okay, unless it stays on when you hold down the reset button…
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Chris, I noticed that when I rotate the encoder, it changes the displayed temperature set point with or without pushing the saftey button and displays the temperature set point all the time. I completely removed the safety button from the circuit but the encoder, when rotated, will still change the temperature set point. The display will show only the temperature set point and nothing else. The operating range that I changed is from 70 to 600. But that seems to be working ok, at least whats showing on the display.
Okay, now we’re getting somewhere…What this means is that your button circuit is wired incorrectly or not functioning. The Rotary Encoder is set up in the code to only work when the button is pushed so your system thinks it always is. If this happens it will not monitor the temperature either so the LED will never go out. The button should be active LOW with a pull-up resistor. You may be missing the pull-up resistor or there is a problem with it. Check that out and let me know.
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That did it Chris. The Display and Temperature Set pushbutton are working correctly now as per your help. See the attachment. I do have another problem though. After powering up the circuit, and letting it run for a few minutes, everything locks up (Saftey Pushbutton no longer works and it will not display the temperature),·and the BS2P-24 is very hot to the touch. The only way to get it to work again is to do a Reset. The chip remains hot but works again for a very short time and locks up once more. This action is repetitious. Is there a way to make the chip run cooler so that the built in thermal protection wont cause a lock up ?
Using the schematic I posted there is no reason why this should happen…It sounds like either the BS2p Module is sinking/sourcing too much current from the I/O pins or the input power supply is higher than 12V to the BS2p module. On my system that cannot happen because I use the Super Carrier Board which regulates the voltage down to 5V into VDD and doesn’t use VIN. If you’re using that board it shouldn’t be a problem. But if you are using something else it could be. I would check for excessive current from the I/O pins.
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That is my impression of what is happening. To much current thru the chip. Here's what I'm using. The USB Board of Education, 9volt 300ma wall power supply, SLED-C4 Led display, BS2P-24 Chip, 1 LED and 1 DS2760 Thermocouple Kit. All is wired as per the Schematic with no addition hardware.
Sounds good to me…Perhaps the module is damaged from something earlier. You did indicate at one point a certain I/O line wouldn’t work but when you switch to a different one it did. Do you have a spare module you could try?
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No spare chip other than a BS2. It has always ran hot from day one. No other circuits have been used with this chip and all handing and wiring precautions were adhered to. The Pin change in the later posts were probably from the overheating in the early stages of use. New Chip Time ?
Installed a new BS2P-24 today and the Solder Pot Controller is working great !!!! No more lock ups and the chip temperature is normal. This is a fantastic circuit and is working as advertised. Thank you Chris. However, I'm curious as to why the displayed temperature will only go down to about 73 degrees and when touching the thermocouple lead to a cold piece of metal or an ice cube, To get a lower reading, the temperature will start to rise (Backwards). The DS2760 with the K-Lead works fine when applying or reducing heat, and Rises and falls normally. Also, is the thermocouple lead for free air only or can it be placed on metal without problems ?
Interesting effect you’re seeing…I have seen temperature go the wrong way when the wires are connected backward in the thermocouple, but then the whole range is messed up so I don’t have an explanation. Here the temperature always starts at room temperature so I haven’t seen anything lower anyway. It is probe dependant as to whether it can be immersed into plastic, metal, liquid, etc. Most probes I have seen will handle anything within their temperature range so long as you keep two factors in mind…One is that the target substance doesn’t interact with the probe in a chemical fashion and corrode or damage the probe chemically. The second is that the target device, if grounded, may cause you to have a ground loop from the perspective of the controller.
This happened to us on the Solder Pot Controller. The Solder Pot is solid metal and is grounded to the pot itself. The tip of the probe we have must be internally connected to the junction (rather than around it) since we had some very weird effects. This was traced to the fact that the controller itself was also grounded putting the BASIC Stamp at the same potential as the Solder Port chassis. Normally this wouldn’t be a problem but the effect was as if you had taken the junction within the probe and grounded it out against the BASIC Stamp VSS. As you might guess this effectively renders the thermocouple inoperable. Because of this the BASIC Stamp controller is now isolated from the power circuit’s ground, which is a good idea anyway. Take care.
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I finally got around to machining out an isolated Thermocouple lead probe tip ( Free Air). It works great. I also did a test where the Thermocouple lead was attached directly to a hot metal specimen. The result was identical. The DS2760 works well with both scenarios....
Yeah, I am still back-logged on getting a couple of circuits around using two Thermocouples but I will get them done soon as post them as well. I’m glad you’re able to get things going. I’ll make sure when I post the other code to post a version compatible with your display. Take care.
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I was just going to build something like this and have a question.
If a nominal duty cycle was input for a starting heating point, could a non touch sensor like the MLX90614 be used to control the temperature of the solder pot. Would simplify the build significantly.
I don’t see why you couldn’t use a non-contact system for temperature measurement. It would greatly simplify the program as well. For our purposes specifically this could never work as we could not guarantee an unobstructed view of the Solder Pot. Whenever something was being dipped the sensor would lose its view and the temperature would be seen as low which would then cause the heating element to come on when it shouldn’t. But for other cases this could work. Take care.
I was also thinking of the problem with sensor obstruction. I was thinking of putting a foot switch for a sensor inhibit. When preparing to dip a board, the switch would prevent the system from changing while the sensor was obstructed. I figure a 3-10 second inhibit period wouldn't be to critical (momentary manual inhibit of course).
I just finished repairing the connector on our lead-free solder pot at work that we use for tinning wires. Three years of thermal fatigue finally got the best of the wires right at the point of crimp terminals inside the connector that attaches to the element. (very similar to an electric skillet connector). I have looked at this project several times and think I need to actually make one now.
any advice for me to start this other than what's already on the thread?
WBA Consulting said...
I just finished repairing the connector on our lead-free solder pot at work that we use for tinning wires. Three years of thermal fatigue finally got the best of the wires right at the point of crimp terminals inside the connector that attaches to the element. (very similar to an electric skillet connector). I have looked at this project several times and think I need to actually make one now.
any advice for me to start this other than what's already on the thread?
If you use the supplied information.....you could build one pretty easy.
If you want to use a non-touch sensor, you will need a foot control or something similar to "pause" the system while the board is dipped.
Other than that, just be careful. Line voltages are not very forgiving to chips or humans.
The only gotcha I recall in this system was keeping the Super Carrier Board from having a common ground with the Solder Pot due to the way the Probe was wired. It did cause me some confusion and ultimately debugging headaches, but once found it was an easy fix. It was pretty straight forward. That said this is one of those projects that had the down side of being a hack on the programming side. I took a program designed to demo the temperature sensor and hacked the code to facilitate the functions I wanted. Very little was stripped from the original. The downside is that customers have reported it difficult to follow. I agree, and if I had it to do over I would have started from scratch. Time was not on my side however, as manufacturing was halted without this piece of equipment.
Chris Savage (Parallax) said...
The only gotcha I recall in this system was keeping the Super Carrier Board from having a common ground with the Solder Pot due to the way the Probe was wired. It did cause me some confusion and ultimately debugging headaches, but once found it was an easy fix. It was pretty straight forward. That said this is one of those projects that had the down side of being a hack on the programming side. I took a program designed to demo the temperature sensor and hacked the code to facilitate the functions I wanted. Very little was stripped from the original. The downside is that customers have reported it difficult to follow. I agree, and if I had it to do over I would have started from scratch. Time was not on my side however, as manufacturing was halted without this piece of equipment.
Hey....with a no touch sensor.....there wouldn't be a probe.
I really need to do this, for we are getting into through hole parts, and we are going to construct our own solder pot.
Comments
Thanks, Twisted Pair....
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Chris Savage
Parallax Tech Support
Thanks, Twisted Pair....
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Chris Savage
Parallax Tech Support
Thanks Chris, Twisted Pair....
Twisted Pair....
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Chris Savage
Parallax Tech Support
Thanks Chris, Twisted Pair....
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Chris Savage
Parallax Tech Support
Thanks Chris....
Thanks once again Chris, Twisted Pair....
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Chris Savage
Parallax Tech Support
Thanks Chris, Twisted Pair....
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Chris Savage
Parallax Tech Support
Thank you Chris, Twisted Pair....
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Chris Savage
Parallax Tech Support
Thank you for all your help, Twisted Pair....
Thank you....Twisted Pair....
This happened to us on the Solder Pot Controller. The Solder Pot is solid metal and is grounded to the pot itself. The tip of the probe we have must be internally connected to the junction (rather than around it) since we had some very weird effects. This was traced to the fact that the controller itself was also grounded putting the BASIC Stamp at the same potential as the Solder Port chassis. Normally this wouldn’t be a problem but the effect was as if you had taken the junction within the probe and grounded it out against the BASIC Stamp VSS. As you might guess this effectively renders the thermocouple inoperable. Because of this the BASIC Stamp controller is now isolated from the power circuit’s ground, which is a good idea anyway. Take care.
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Chris Savage
Parallax Tech Support
Thanks Chris, Twisted Pair....
Twisted Pair....
Yeah, I am still back-logged on getting a couple of circuits around using two Thermocouples but I will get them done soon as post them as well. I’m glad you’re able to get things going. I’ll make sure when I post the other code to post a version compatible with your display. Take care.
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Chris Savage
Parallax Tech Support
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I was just going to build something like this and have a question.
If a nominal duty cycle was input for a starting heating point, could a non touch sensor like the MLX90614 be used to control the temperature of the solder pot. Would simplify the build significantly.
James L
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James L
Partner/Designer
Lil Brother SMT Assembly Services
Please note: Due to economic conditions the light at the end of the tunnel will be turned off until further notice. Thanks for your understanding.
I don’t see why you couldn’t use a non-contact system for temperature measurement. It would greatly simplify the program as well. For our purposes specifically this could never work as we could not guarantee an unobstructed view of the Solder Pot. Whenever something was being dipped the sensor would lose its view and the temperature would be seen as low which would then cause the heating element to come on when it shouldn’t. But for other cases this could work. Take care.
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Chris Savage
Parallax Engineering
50 72 6F 6A 65 63 74 20 53 69 74 65
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I was also thinking of the problem with sensor obstruction. I was thinking of putting a foot switch for a sensor inhibit. When preparing to dip a board, the switch would prevent the system from changing while the sensor was obstructed. I figure a 3-10 second inhibit period wouldn't be to critical (momentary manual inhibit of course).
But thanks for the reply.
James L
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James L
Partner/Designer
Lil Brother SMT Assembly Services
Please note: Due to economic conditions the light at the end of the tunnel will be turned off until further notice. Thanks for your understanding.
Post Edited (James Long) : 9/24/2009 12:47:08 AM GMT
any advice for me to start this other than what's already on the thread?
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Andrew Williams
WBA Consulting
WBA-TH1M Sensirion SHT11 Module
Special Olympics Polar Bear Plunge, Mar 20, 2010
If you use the supplied information.....you could build one pretty easy.
If you want to use a non-touch sensor, you will need a foot control or something similar to "pause" the system while the board is dipped.
Other than that, just be careful. Line voltages are not very forgiving to chips or humans.
James L
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James L
Partner/Designer
Lil Brother SMT Assembly Services
Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits. Learn to build your own Gizmos!
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Chris Savage
Parallax Engineering
50 72 6F 6A 65 63 74 20 53 69 74 65
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Hey....with a no touch sensor.....there wouldn't be a probe.
I really need to do this, for we are getting into through hole parts, and we are going to construct our own solder pot.
James L
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
James L
Partner/Designer
Lil Brother SMT Assembly Services
Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits. Learn to build your own Gizmos!