Touch screen in current design is the only way that guarantee AC softstart (due to Arduino "feature" #96).
Some brainstorming here about a possible workaround for this startup issue.
The idea is to use the voltage monitoring in IC31 TPS3705-33D to delay the control of PWR_DIRECT and PWR_SSTART and “wait out” the 10ms pulse from the Arduino.
PFO will be held low and block PWRSS and PWRDIR until R1 has charged up C to the level that input PFI goes above 1.25V.
From the datasheet (see picture), this level is calculated as: VTH=((R1+R2)/R2)x1.25
Have I missed something?
Ha, ha, you can but don't expect precision in ppm .
Therefore your suggestion with power-up delay should work only if it's somehow added to end of RESET pulse (e.g. additional 30 or more milliseconds).
Thanks!
I have seen that video, but it was about then you released it, so obviously I didn’t remember it all correctly...
Another observersion:
With the output On I am able to go “over” the 310W limit (e.g. over 4A@80V) if I use the steps. It is also possible with the rotary encoder if it’s done slowly, about max one step per second.
If it has been set “too high”, the keypad is the only way to go back down again if the output is Off. Step, slide and rotary encoder are all blocked by the “Power limit exceeded” warning.
If the output is On it is possible to go back down the same way it is possible to go up over the limit.
Thanks!
I have seen that video, but it was about then you released it, so obviously I didn’t remember it all correctly...
Another observersion:
With the output On I am able to go “over” the 310W limit (e.g. over 4A@80V) if I use the steps. It is also possible with the rotary encoder if it’s done slowly, about max one step per second.
If it has been set “too high”, the keypad is the only way to go back down again if the output is Off. Step, slide and rotary encoder are all blocked by the “Power limit exceeded” warning.
If the output is On it is possible to go back down the same way it is possible to go up over the limit.
Hm, this is interesting. I tried it just now, outputs are coupled in series, current is set to 4 A and, output is on, and with slowly increasing output voltage I'm repeatedly get error message on attempt to go over 77.50 V that is right (77.5 x 4 = 310). I need more input here.
Therefore your suggestion with power-up delay should work only if it's somehow added to end of RESET pulse (e.g. additional 30 or more milliseconds).
It looks like there is ~200ms from 3V3 is live to RST=1 and after that we need another 25ms delay of the and gate. Right?
A quick test on the bench with 100k for R1 and R2 and 1uF for C gave a delay of about 60ms until 1.25V was reached.
If R1 is feed from RST out on IC31 (pin.7) instead of the 3V3 rail, the 60ms delay will not start until RST goes high.
Therefore your suggestion with power-up delay should work only if it's somehow added to end of RESET pulse (e.g. additional 30 or more milliseconds).
It looks like there is ~200ms from 3V3 is live to RST=1 and after that we need another 25ms delay of the and gate. Right?
A quick test on the bench with 100k for R1 and R2 and 1uF for C gave a delay of about 60ms until 1.25V was reached.
If R1 is feed from RST out on IC31 (pin.7) instead of the 3V3 rail, the 60ms delay will not start until RST goes high.
We are almost there. Only what is missing is AND-ing instead of OR-ing PFO and WDO outputs.
EDIT: without introducing more components maybe we should tied permanently WDO to MR input (JP8 is out) and connect PFO to IC29A input.
Yes but, WDO is on the power-up high and in that way cancels effect of delayed PFO. With minimum additional components it should looks like this:
WDO will now generate reset if watchdog failed (i.e. firmware stuck).
You're right, but I'll stay with solution in my previous post. No need to introduce two more components. I think that we also we don't need 100K on previous R160 position (if diode are not using). PFO and WDO are not open collector outputs.
I'll try to modify my Arduino shield and let you know how it looks like.
D21 is added that IC31 output not interfere with reset generating by Arduino IDE during before firmware upload is begin. I'll check if that side of diode is appropriate to charge capacitor.
What was your thought then getting the charging from outside (anode) D21?
Thanks!
I have seen that video, but it was about then you released it, so obviously I didn’t remember it all correctly...
Another observersion:
With the output On I am able to go “over” the 310W limit (e.g. over 4A@80V) if I use the steps. It is also possible with the rotary encoder if it’s done slowly, about max one step per second.
If it has been set “too high”, the keypad is the only way to go back down again if the output is Off. Step, slide and rotary encoder are all blocked by the “Power limit exceeded” warning.
If the output is On it is possible to go back down the same way it is possible to go up over the limit.
Hm, this is interesting. I tried it just now, outputs are coupled in series, current is set to 4 A and, output is on, and with slowly increasing output voltage I'm repeatedly get error message on attempt to go over 77.50 V that is right (77.5 x 4 = 310). I need more input here.Try to increase current instead of voltage in cc mode.
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Tried but still without success. I set voltage to 80 V, connect 16R4 load to be in CC mode and starts to change current and cannot go over 3.87 A.
Tried but still without success. I set voltage to 80 V, connect 16R4 load to be in CC mode and starts to change current and cannot go over 3.87 A.
This phenomenon seems to rise with lower load resistance.
At 15 ohm I also got a stable behaviour, but under ~10 ohm it went easier and easier.
With a 3 ohm load I have no problem to reproduce it.
I can confirm this with smaller load: tested with 2R, voltage set to 80 V, in CC mode I can slowly increase current up to 5 A (i.e. 400 W). Do you mind to open this as new issue in GitHub for firmware?
I can confirm this with smaller load: tested with 2R, voltage set to 80 V, in CC mode I can slowly increase current up to 5 A (i.e. 400 W). Do you mind to open this as new issue in GitHub for firmware?Ok. #183
Are you receiving **ERROR: -243,"CH2 fault detected" also in CV mode?