Atten SMD tweezers: need soldering station schematic (ST-1509 or GT-6200) HELP

[riccardo.pittini]

Hi

I am working on a new version of a hobby soldering station. The first version I made (SolderingRT1, https://gitlab.com/pittinihub/solderingrt1) works very well with Weller RT tips and tweezers.
However, I wanted to add functionality and make it compatible with other tips (like JBC and others).
The Weller tweezers are expensive and recently Atten made some similar ones (example: ST-1509 N9100). These are very similar to Weller ones.

Example:
https://www.aliexpress.us/item/3256803404139133.html?gatewayAdapt=glo2usa4itemAdapt


The Atten tweezers ST-1509- N9100 have a very similar structure as Weller. They work with 12V (3R resistive element) and have a thermocouple.
The connections are the following: HeaterLeft, TCleft, GND, TCright, HeaterRight. The thermocouple type is different than the Weller but, I can fix that with a proper calibration and mapping.

Now the main challenge:
- In the Weller tweezers the TC are reference to GND and they generate a positive voltage compared to GND like few mV that then get amplified etc..
- In the Atten tweezers the TC seem reference to GND but "inverted polarity" so actually they generate a negative voltage on the TCpin

As the voltage on the Atten tweezers is negative I cannot the normal amp stage I used before. A solution would be using a differential amplifier with dual supply and adding an offset to it. However, this adds expensive opamps (I am trying to make it KISS style) and a bit of complexity.
So I wanted to try to get inspiration from Atten designers .

Does anyone has an Atten station (ST-1509 or GT-6200) and can post some pictures of the PCBs /teardown?
Or does someone has a schematics for those stations?

Thanks everyone

[2N3055]

Are you sure about polarity of TC?

Mine certainly does not generate negative signal in reference to ground.. It will generate approx. 10 mV at 400 °C.
You need noninverting amp 250-300x to bring it into 3.3V range.  You will need to experiment to calibrate it correctly.

Don't measure while current is flowing into heater because heater and TC have common return wire.

[2hry]

Hi
I dont have an atten station, but i have ordered only the tweezers.
Like you, I also thought I´d make my own controller, and noticed the negative voltage referenced to ground.

I´m going to try it like that, when my pcbs arrive(approx. 2weeks) made Dual Resistors -- marked green:Atten -- other side: Weller

[2N3055]

Hi
I dont have an atten station, but i have ordered only the tweezers.
Like you, I also thought I´d make my own controller, and noticed the negative voltage referenced to ground.

I´m going to try it like that, when my pcbs arrive(approx. 2weeks) made Dual Resistors -- marked green:Atten -- other side: Weller

Heat up the tip. It is not negative  when hot. It might be some µV at room temp. But as soon as you heat it up it gets into positive mV range.

That is for GT-N100.

[riccardo.pittini]

It is negative like 8mV at 340C. I probably measure it 10 times, checked re-cheked multimeter cables etc... That's just how it is and very annoying...
 
Calibration is not a problem (the one I have doe with the Weller resulted in a temp in +-1C )

[riccardo.pittini]

Thanks for confirming also the negative voltage . I thought I could use the same station I made for Weller but... nope..
Nice schematics and thoughts.

In my head I was trying to design a universal front end that could work with Weller, JBC, Atten etc. I think I might try to make a precision differential amplifier with offset. So with a ref of 3.3V for the ADC and 0V from TC the ADC input stays at 1.650V.
So if TC has a normal positive voltage it the ADC voltage will be from 1.65V to 3.3V and if the TC has a negative voltage then it will be from 1.65V to 0V.

[riccardo.pittini]

I got myself this: T9100-0.5I from
https://www.aliexpress.us/item/3256804993168682.html?spm=a2g0o.order_list.order_list_main.127.1b8a1802sLRvon&gatewayAdapt=glo2usa4itemAdapt

Maybe GT-N100 are different?

[2hry]

mine is called T9100-1.3D
Those are my first soldering tweezers, because they were always to expensive.

Universal frontend: I like the idea but what about the KISS principle?

[2N3055]

It is negative like 8mV at 340C. I probably measure it 10 times, checked re-cheked multimeter cables etc... That's just how it is and very annoying...
 
Calibration is not a problem (the one I have doe with the Weller resulted in a temp in +-1C )

Funny.

I have 2 GT-N100 tips (from TME, real original Atten) and both are definitely positive voltage..

[thm_w]

Universal front end is do-able but honestly, just build two boards and have it hardware configured for one specific iron if possible.
You don't want multiple connectors going to the same board anyway, in case you connect up two handpieces at the same time. And you'll be hard-wiring a specific connector for a specific brand.

Supporting JBC alone is very complex. But I would start by adding current sensing to your existing design. You can replace the FETs with smart automotive switches, for an easy solution.
You can look at how they handle switching using analog muxes.

[riccardo.pittini]

Yes in the new design there will be current sensing. I will still use regular FETs (they are easy to driver, I will add Cdg for better control of di/dt).
Probably in future I might try to integrate a PGA to have variable gain for better using ADC with various TC types.

What do you mean with "smart automotive switches"? Why do you think supporting JBC is complex?

For 2N3055: If you have time and opportunity..
Could you try on a SMD tweezers tip (without cable only tip replacement) to measure the TC voltage with a millimeter in mV range?
Connections are: HeaterLeft, TCleft, GND, TCright, HeaterRight
You cannot measure the TC voltage with the power applied (it would be off and you would measure just noise). Heat-up with another iron tip one side fo the SMD tweesers and measure the TC voltage.
I'm very curious about the result
 

[2N3055]

Yes in the new design there will be current sensing. I will still use regular FETs (they are easy to driver, I will add Cdg for better control of di/dt).
Probably in future I might try to integrate a PGA to have variable gain for better using ADC with various TC types.

What do you mean with "smart automotive switches"? Why do you think supporting JBC is complex?

For 2N3055: If you have time and opportunity..
Could you try on a SMD tweezers tip (without cable only tip replacement) to measure the TC voltage with a millimeter in mV range?
Connections are: HeaterLeft, TCleft, GND, TCright, HeaterRight
You cannot measure the TC voltage with the power applied (it would be off and you would measure just noise). Heat-up with another iron tip one side fo the SMD tweesers and measure the TC voltage.
I'm very curious about the result

Riccardo,

I know layout. I posted TC voltage above: approx 10mV at 400°C. Positive.
It will be 8 mV at 310-320°C soldering range..
Around 2 mV at 100°C
At room temperature (23°C) they show slightly negative few µV. If I heat it only with hand it goes slightly positive. I presume 0 µV point is around 25-30°C
It is pretty much linear..

I have two tweezers, both are same.
Bought from TME, original Atten

Best,

Siniša

[thm_w]

Yes in the new design there will be current sensing. I will still use regular FETs (they are easy to driver, I will add Cdg for better control of di/dt).
Probably in future I might try to integrate a PGA to have variable gain for better using ADC with various TC types.

What do you mean with "smart automotive switches"? Why do you think supporting JBC is complex?

A smart FET allows a simple on/off input and can manage short circuit and overtemperature scenarios automatically. Some also have current sense output. Its not necessary, but, nice way to avoid a lot of design effort. Here is a random example: https://www.onsemi.com/download/data-sheet/pdf/ncv84045-d.pdf

JBC is very complex to fully support once you get into the C115 and tweezers, as they don't use the same pinout.

[2hry]

Pcbs arrived.
My Aliexpress sourced Tweezers work like that.
That is different than any other iron i know.

I have modified the code from Wagiminator´s Github "AtmegaSolderingStation" for two irons.

By changing the resistors, i can drive Weller RT, Jbc210, or Jbc115 at 9V. 2 Irons with one station.
My chinese Relife branded C115 has the same pinout as C210.

[riccardo.pittini]

Thanks for re-checking Just cannot get my head around the differences
(seems like there are two types around or Atten has designed a frontend that does not care about Tc polarity  )

[riccardo.pittini]

Same measurements I have Very nice build with oled dispaly!!

If you need a quick conenctor : https://vi.aliexpress.com/item/1005005245687334.html?spm=a2g0o.order_list.order_list_main.98.6dc91802ZmBsQ6&gatewayAdapt=glo2vnm

They are basically a battery connector 5pin 100mils female. I actually just saw that in your picture you can solder directly the connector on your custom board

[2hry]

Thanks for the tip with the connector. I could use a usb pd adapter and use it alone.

The plan was to use a cable, and a station with stand for sleep mode.
 

[riccardo.pittini]

I couldn't believe it myself unless I saw it.. :O
Atten made TWO types of SMD tweezers. One is called T9100 and one T100.

- The one with negative voltage on the TC are the T9100
- The ones with positive voltage on the TC are the T100
Internal wiring is the same.

So the ones I bought online were the T9100 model with negative voltage. Then at work we bought an evaluation unit (GT6200) for expanding the lab so I took the occasion to look at the tweezers. In this case the model is T100 (positive Tc).
The GT6200 are compatible with only the T100 not with the T9100.

I hope this helps some people and some clarifications. I am still very surprised that they sell two almost identical tweezers (apart from the name) with no clear clarification.

[riccardo.pittini]

FYI ALL, I also got finally an official reply from Atten:

Q: What is the difference between "T100-0.5I" and "T9100-0.5I" ?
Are they compatible with each other?
 
A: The sensors of T100-0.5I and T9100-0.5I are different. And the temperature signals size are different also.
So they are NOT compatible.
 
These two models of tweezers can match the housing as below. Hope it can help you better.
T100-0.5I Applicable model：
GT-6150
GT-6150P
GT-6200
GT-6200P
GT-5150
MS-900

T9100-0.5I Applicable model
ST-1509