Author Topic: Serial to usb on Kunkin KP184 electronic load  (Read 4298 times)

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Offline belzrebuth

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Re: Serial to usb on Kunkin KP184 electronic load
« Reply #25 on: July 03, 2020, 08:41:13 am »
Is there a guide somewhere on how to setup the USR-232-T2 ethernet to RS232 module?
I've managed to connect to it via LAN but I think it needs a serial to TTL converter (3.3 to 5V in order to work with the KP184)
The FTDI clone I have does now work with the load.
It has a FTDI chip so there must the level conversion again that's probably incompatible.
Could it work with a diy level shifter?
I've seen some designs with a couple of transistors..
« Last Edit: July 03, 2020, 12:47:47 pm by belzrebuth »
 

Offline coromonadalix

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Re: Serial to usb on Kunkin KP184 electronic load
« Reply #26 on: July 03, 2020, 02:24:51 pm »
The one i use the most is  a model  sp-880   usb to rs232, it as a real ft232 with an transceiver ic   betwwen the rs232 plug and the ftdi chip

maybe some other source ??

https://www.amazon.ca/Connectors-SP-880-UT-880-Compatibility-Yoton/dp/B07Q6HW46V


https://botland.com.pl/en/converters-usb-to-uart-rs232-rs485/4371-ft232rl-sp-880-usb-converter-rs232-com-10v-with-db9-connector-adafruit-18.html
 

Offline belzrebuth

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Re: Serial to usb on Kunkin KP184 electronic load
« Reply #27 on: July 03, 2020, 02:38:01 pm »
Mine has a jumper for 3.3V or 5V operation.
I've set it for 5V and still nothing.
The adapter is working because I use it very often so maybe it's their combination that's somehow problematic.

My settings on the Kunkin are :
address 001, baud rate 19200.
And on the adapter I've set the baud rate to 19200 and N 8 1 with delay 100mSec.
I've checked the RX and TX pins of my FTDI adapter and they're both 5V when I set the jumper to 5V so it's not the voltage level..
I've tried both the modbus cmd program and kp184 modbus program from interflexo.
But I get no answer from the load.. :-//
Here's the output when trying to run the modbus KP184.exe (I switched my baud rate to 9600 just in case) :
 
Verbose  17:47:19.664 port                :COM Port: com4
Verbose  17:47:19.675 baud                :BAUD rate: 9600
Verbose  17:47:19.676 delay               :Sleeping for 100ms
Verbose  17:47:19.786 address             :Device address: 1
Verbose  17:47:19.789 get_status          :Calling get_status from KP184
Verbose  17:47:19.795 open                :Opening serial port 'com4' at 9600 baud
Error    17:47:20.884 read                :Timeout reading from com4
Error    17:47:20.890 Main                :Checksum error, got 0x0000. expected 0x1B1B

I'm using a female DB9 connector with pins 2,3,5 being pins RX, TX, GND of my FTDI respectively.
« Last Edit: July 03, 2020, 03:03:51 pm by belzrebuth »
 

Online HKJ

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Re: Serial to usb on Kunkin KP184 electronic load
« Reply #28 on: July 03, 2020, 04:26:22 pm »
Mine has a jumper for 3.3V or 5V operation.
I've set it for 5V and still nothing.
The adapter is working because I use it very often so maybe it's their combination that's somehow problematic.

Try measuring the voltage on the DB9 connector, if it is a RS232 output it is more than +/-9V and will not work directly with a TTL level adapter with 3.3V or 5V, both the voltage and polarity will be wrong.
 

Offline belzrebuth

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Re: Serial to usb on Kunkin KP184 electronic load
« Reply #29 on: July 03, 2020, 04:56:56 pm »
I'm getting 5V at pin 2 (with 5 being the negative) and 5V at pin 7.
That's on the Kunkin connector.
5V should be the TX pin (from the manual) and should go to the RX pin of the adapter and vice versa for the other RX and TX.
That's what I've done and it's not working.
I could try another USB to serial adapter I guess..but I suspect there might be a connection issue of some sort since this FTDI tool has worked with everything I've thrown at it and it has a FTDI chip which essentially what most of the working adapters reported here have as well.
I've ordered a couple of other adapters but they won't be here anytime soon so I will try to verify if there's a connection issue.
« Last Edit: July 03, 2020, 05:04:56 pm by belzrebuth »
 

Offline coromonadalix

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Re: Serial to usb on Kunkin KP184 electronic load
« Reply #30 on: July 03, 2020, 06:09:00 pm »
If you are under windows, dont forget in the device manager  to set  higher baud rates for the usb rs232 adapter, it default to 9600 bauds, i always set them to 115200 bauds  ...  had a stupid problem in the past because of this  :palm:
« Last Edit: July 03, 2020, 06:11:32 pm by coromonadalix »
 

Offline belzrebuth

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Re: Serial to usb on Kunkin KP184 electronic load
« Reply #31 on: July 03, 2020, 06:47:34 pm »
Okay I'll try higher baud rate and report back!
 

Offline aristarchus

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Re: Serial to usb on Kunkin KP184 electronic load
« Reply #32 on: July 07, 2020, 01:00:53 am »
Hi,

Just recently received my KP184 and tried to use the RS232 port.
Initially tried with a USB to UART simple little board but it was not working.
https://www.aliexpress.com/premium/FT232RL-USB-to-TTL-Serial-Adapter-Module.html
Then I understood that it is indeed a RS232 port on the KP184 and not a UART, thus I added a small MAX RS232 level converter
https://www.aliexpress.com/premium/MAX3232-Level-to-TTL-Level-Board.html
between the USB to UART board and the KP184 RS232 port and now it is working just fine up to the full 115200bps.

So if someone wants to have something that works and not endlessly searching for the proper adaptor, that is a working solution.
Tried it with modules having fake and original FTDI chips, its just the same, both work ok.


PS
Added a photo of level converter and USB to UART.
« Last Edit: July 07, 2020, 10:09:12 am by aristarchus »
 

Offline aristarchus

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Re: Serial to usb on Kunkin KP184 electronic load
« Reply #33 on: July 10, 2020, 07:28:18 pm »
Also tested the RS485 port on KP184.
Used two solutions, first adding a TTL/UART to RS485 board instead of the RS232
https://www.aliexpress.com/wholesale?catId=0&SearchText=ttl+to+RS485
which worked just fine.
Then tested a ready made USB to RS485 for less than 2 bucks
https://www.aliexpress.com/wholesale?SearchText=USB+FTDI+TTL%2FRS485
which again worked ok.
 

Offline aristarchus

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Re: Serial to usb on Kunkin KP184 electronic load
« Reply #34 on: July 21, 2020, 11:01:53 am »
Managed to find the KP184 modbus protocol specification.
I hope it can be of use and developers could add all functionality in their programs.
 
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Offline interflexo

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Re: Serial to usb on Kunkin KP184 electronic load
« Reply #35 on: November 24, 2020, 04:34:27 pm »
New KP184 Software Version 1.0.5.0:

Changes:

1. Fixed some data logging hiccups during application main window drag
2. Fixed graph y-label slightly clipped
3. Several support modules were updated in the Python ecosystem.

KP184_Software V1.0.5.0
User_Manual

Just use the new .EXE file over your previous v1.0.4.0 installation to preserve your configuration.
« Last Edit: November 24, 2020, 05:26:44 pm by interflexo »
 


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