TS100 soldering iron -- Ralim firmware, menu question

[ebastler]

I have installed Ralim's open source firmware on my TS100. There is a short documentation page on the menus, which suggests that one can select the tip model (and should, to ensure the temperature control parameters are correct).

Tip Model Selection
The menu now lets you select which tip you are using with your iron. This lets the unit know which gain value to use for your tip, this varies slightly between models and can help with temperature accuracy. There is also an option for a custom tip. This basically means that you will tune the tip parameters yourself.

https://github.com/Ralim/ts100/blob/master/menu.md

But where would I find that menu item? I have worked my way through the settings menu and its sub-menus, and have looked at the gui.cpp source code. Am I overlooking something? Or has this been removed from the current version (2.11), and the documentation is outdated?

[Gyro]

Afaik, that menu option has been dropped from the latest version (at least I haven't found it!). It was there on the previous version* but only had a couple of tip options. Ralim has gone through a lot of iterations in his attempts to optimize the PID (check out the closed issues) and that was one of them - effectively hard specifying the tip thermal mass.

So yes, the documentation looks to be a bit out of date. The latest version certainly seems to be the best yet in terms of temperature regulation and recovery though. I recently bought a C4 tip, just for for heavy work, and it really kicks out some power against the biggest thermal masses.


Edit: * Make that the last but two, I hadn't noticed the Aug 29 release!

[magic]

Soldering iron with DC PWM?

How big are the voltage spikes at the tip?

[Gyro]

Depends on the tip grounding arrangement (see ebastler's recent thread). I see less than 0.2V on my shared tip ground and -ve wiring arrangement.

Soldering iron with DC PWM?

Why the surprise? They all use DC PWM - Hakko and all the T12 variants as far as I know [Edit: all of the SMPS powered ones anyway].

[ebastler]

Afaik, that menu option has been dropped from the latest version (at least I haven't found it!). It was there on the previous version* but only had a couple of tip options. Ralim has gone through a lot of iterations in his attempts to optimize the PID (check out the closed issues) and that was one of them - effectively hard specifying the tip thermal mass.

Ah, thank you! Good to know that I'm not going blind... If the temperature control has been optimized such that it doesn't need to know the specific tip type, that's even better.

[magic]

Why the surprise?

Because I remember it being more of a problem in my DIY driver for Hakkos. Maybe due to the long cable between the station and the iron. 0.2V isn't too bad.

I thought the commercial SMPS stations use modulated rather than pulsed DC.

[Gyro]

Hmm I don't know now -  I assumed that any of the ones with an SMPS would be PWMing the DC, as they need to be able to read back the thermocouple temperature too. When I said SMPS ones I was contrasting with the older transformer based triac switched ones.  I'm not quite sure what you mean by modulation though (other than pulse width).

I suppose low tip noise may be to do with having the mosfet right in the handle, allowing a much shorter current loop area (at least for high frequency edges) using local decoupling. Obviously it's still going to be modulating the lower frequency elements of the PWM onto the supply cable*... Direct tip grounding (rather than through the cable -ve) is always going to be cleaner, if less convenient.

Edit: * I just did a quick scope check - rise/fall times (Mains/PSU ground - Tip) seem to be around 1ms.


P.S. Sorry, the above doesn't make much sense in isolation - I should have referenced the other recent TS100 thread https://www.eevblog.com/forum/projects/silicone-lead-for-soldering-iron-recommendations/ regarding voltage drop and tip grounding.

[magic]

I meant variable DC, depending on momentary power requirement. Think SMPS whose (primary) duty cycle is throttled by tip temperature rather than secondary voltage.

On second thought, that would require an auxiliary constant voltage supply for the temperature monitoring circuit, so maybe they don't bother with it.