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Test Equipment / Re: Agilent U1177A IR to BT adapter
« Last post by Kean on Today at 04:22:15 pm »
I think the next step is to see if I can get an old BT USB dongle and rule out the Intel BT HW.

Agreed.  Most old USB dongles should support BT 2.1, but may not support BLE.
Windows 11 is supposed to still have full support just like Win 10, but I've avoided upgrading any of my PCs.
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Microcontrollers / Re: TCP Client/server best practice
« Last post by ejeffrey on Today at 04:19:35 pm »
Also true, I have used an embedded system that leaked file descriptors when you opened and closed sockets, and only had 256 elements in the file descriptor table.  We had to implement aggressive connection reuse, count the number of connections made, and schedule a reboot when it got too high.  Other systems like those based on Wiznet chips have a very limited number of simultaneously open sockets, so if you keep the socket open you block anyone else trying to use it.  In this case if you let the sockets remain open and a connection drops without being shutdown cleanly due to a firewall timeout, power loss, network disconnect, or other disruptive event, the system can become unresponsive.  Here it's better to close sockets immediately so they can be reused, and also aggressively timeout sockets that hang before completing their transaction.  These are generally problems with very limited embedded systems especially when you don't have access to the software.

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Yes, you got it right.

Quote
not sure why they list DC efficiency.
Just to offer more detailed information for those interested. Indeed it's not very relevant for end user if the only use case is through the AC inverter-charger. Battery chemistry and voltage ranges is similar extra information; just for reference.
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If you bought the 34410A new and with that bug you should have contacted the seller or keysight to get it fixed.

Beside that

1) Specs 34410A>34461A
2) I don't have to wait 2 months after pressing the on/off button
3) We have the 34410A schematics, which for me double the value automatically

My personal opinion. Please do not think or assume the 34461A is bad device, for $800 shipped is a good deal go for it if you need one!

yes the fan 34410A is noisy, but you can mitigate that problem.
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Test Equipment / Re: Hacking the Rigol DHO800/900 Scope
« Last post by Mechatrommer on Today at 04:15:53 pm »
The following is the logical pseudocode for a few key functions:
so the RK3399 pins 122-126 are set as output, and then later stage  gpio_afg_drv_read read them as if they are input? hmm confusing... ;D

The following is the logical pseudocode for a few key functions.
It is still unclear how the RK3399 GPIO_122~GPIO_126 corresponds to the pins of the AD9744 DAC, and you need to explore. Good luck!
I'm pretty sure that the AFG board gets the 14 bit DAC data from the FPGA.  The GPIO's you identified might be for setting gain, offsets, etc..?
My Hypothesis: The GPIO's you identified might be to/from AFG board. (to set gain, offsets, etc..?)
I imagine that afg_gpio.ko driver just provides module status detection, or other configurations, and the specific 14-bit data is transmitted through the FPGA, since it only has 5-bit data.
see attached my attempt rev eng afg pins interface. so far there are only 3 unknown pins UP0, UP1, UP4 (pin 10 on smaller interface and pin 22 and 28 on larger interface) red arrowed in pcb picture and highlighted green on the connector diagram. i didnt bother to check to where they are connected. probably to FPGA, or RK, or to other passive/semi components before going to either one of them. the ultimate reference provided by you still unclear about them, UP0 seems near some inductor, resistors and cap network, not sure what it is, on my UTG962 AWG, there is some kind of protection mechanism to cut off output in case AFG output is exposed to excessive external DC, so i'm guessing UP0 is probably it.

anyway lets assume just for sake of simplicity those 3 are connected directly to RK and being read or written by afg_gpio.ko, there are still 2 GPIOs unknown... so.. fwiw ymmv...

nomenclature:
DB = DAC digital input
CLK = DAC clock
REL = relays control

AFG OFFSet and AMPLitude signal will only present when we install the 2 missing opamps TP1282 (i used OPA2350). later finding.. pin 28 will be low for 4ms each time bode plot feature is started and then goes back high forever until bode plot is restarted again...
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This is beyond EPIC.
uch appreciated.
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Microcontrollers / Re: TCP Client/server best practice
« Last post by Siwastaja on Today at 04:04:45 pm »
As others have expressed, both strategies are valid, and if you use non-broken TCP/IP stacks on both ends, both will work just fine: TCP is guaranteed to never lose a byte, so sending requests and then parsing until you know you have full response* will work indefinitely. On the other hand, opening and closing TCP socket is not that expensive operation at all, so no problem there either. If we were discussing linux or BSD stacks, there would be no problem: they are basically bug-free.

*) if the protocol makes it difficult to detect "full reply" condition, then strategy A would be simpler.

Now if you need to use some broken code, possibly in some closed black box system which you cannot fix, things get different: then it is well possible that either one of the proposed strategies is more likely to trigger a catastrophic bug, than the other. Which one, is then matter of luck (which kind of bug is triggered exactly); so prepare to implement both strategies. Maybe the internal state is corrupted every now and then; then fresh connection each time is better. Or maybe closing socket does not release all the resources, and memory (or some other resource) runs out after 1000 sockets. Then a single socket strategy would easily offer uptime of years, single-use sockets would run out in hours.

We are currently having pretty bad times with a (Western) brand hybrid solar inverter which implements MODBUS TCP, but they stop working and start timeouting when trying to open a socket, randomly after a few days to few weeks, so that end customers need to reboot them. There's not much we can do about it, except try to figure out if some specific use pattern we do is more likely to trigger the bug, plus discuss with the manufacturer and hope they can fix their thing, but then again our customers complain to us and our partners installing those inverters so we can't just say "oh, you bought a faulty inverter" after they made >10000EUR investment.

This hurdle has taught us stuff like MODBUS TCP has been a big mistake. Compared to e.g. RS485 based Modbus RTU, it's a huge security issue because in practice, it always will connect to the internet; the fallacy of "safe internal network" was not well understood in 1990's. And then, it adds a lot of extra complexity by requiring TCP/IP stack, which would be easy-peasy if the devices were general purpose computers with auto-upgradeable general purpose operating system (like linux or BSD or even Windows CE or something like that), but they are not, instead they run any random TCP/IP stack quickly cobbled together and tested in lab conditions. What's worst, embedded device manufacturers who are not exactly specialized in IoT (like solar inverter manufacturers) have no incentive to really fix bugs and offer firmware updates.
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It was a few years ago that I last tried it, but I don't think you can mix repeat with busses.  I had to either split the bus into individual signals, or forget the repeat and just place separate instances of the block that used busses.
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Just purchased and installed an Enphase 5p battery.  Could someone please explain what is meant by

AC round-trip efficiency 90%  (AC to the battery to AC at 50% power rating) 
DC round-trip efficiency 96%

The 5p only has AC terminals for charging and load so not sure why they list DC efficiency. (There is no way to DC charge.)

I'm guessing the RT AC efficiency means if 1kWhr is used to charge the battery I will only get 900 Whrs back when discharging.  (Provided the discharge load on the batteries is at 50% of the continuous capacity load 3.84 kWhr.)

Thanks

https://enphase.com/download/iq-battery-5p-data-sheet
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