Nonlinear Posted March 1, 2021 Share Posted March 1, 2021 Hi Everyone, Can anyone provide me with suggestions for reputable RS232/USB converters. Preferably I would like recommendations for converters using the PL2303 chipset (because I know it is well supported under both Linux and Windows). I would also like to hear members opinions on isolation or opto-isolation on these converters to ensure that surges and other nasty effects are not sent through to the expensive equipment connected on the RS232 side. As you can probably guess I lost some equipment due to a surge transmitted on the converter to batteries and inverters which fried the comms on these devices. As a bonus, it would very much be appreciated if these were obtainable in South Africa. Quote Link to comment Share on other sites More sharing options...
P1000 Posted March 1, 2021 Share Posted March 1, 2021 (edited) I like the FTDI stuff. You can get them from RS, but they are a lot more expensive than others. You will probably find what you want at Micro Robotics (PL2303). On opto-isolation: That could work but it is probably not going to be that simple - you need to arrest the surge and make sure it stops before the isolation barrier (on both sides) and have a fuse of sorts and enough distance to prevent breach. I have seen a number of very well designed isolation interfaces that failed to actually stop the surge from propagating simply because it is really difficult to do well in the real world. I like the ADuM range of digital magneto-isolators for communication, but they require power on both interfaces. Edited March 1, 2021 by P1000 Quote Link to comment Share on other sites More sharing options...
Nonlinear Posted March 1, 2021 Author Share Posted March 1, 2021 I saw the FTDI stuff on RS (because I buy there anyway for business reasons) but I was not sure if it would work. I am almost at the point where I would say cost is a minor/secondary issue simply due to the immense inconvenience/time/money involved when a surge damages the communications on some of your kit. It has taken months of haggling with the bank and quite a large amount of my own money to get my solar system back online. I'll have another look at the FTDI and I will also read up on the ADuM (is that Analog Devices or just a coincidence?). Thanks for taking the time to post. Quote Link to comment Share on other sites More sharing options...
P1000 Posted March 1, 2021 Share Posted March 1, 2021 By ADuM I mean something like this: https://za.rs-online.com/web/p/digital-isolator-ics/4967519P/ For sure arresors maybe 1ohm through-hole resistors going to these: https://za.rs-online.com/web/p/tvs-diodes/0508018/ (PESD12VL2BT,215) Quote Link to comment Share on other sites More sharing options...
Nonlinear Posted March 3, 2021 Author Share Posted March 3, 2021 Thanks @P1000 I'm happy to report the FTDI converter works. Results of dmesg [160585.535658] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [160585.535666] usb 1-1.4: Product: US232R [160585.535672] usb 1-1.4: Manufacturer: FTDI [160585.535679] usb 1-1.4: SerialNumber: FT4WLQTJ [160585.571538] usbcore: registered new interface driver ftdi_sio [160585.571583] usbserial: USB Serial support registered for FTDI USB Serial Device [160585.571745] ftdi_sio 1-1.4:1.0: FTDI USB Serial Device converter detected [160585.571823] usb 1-1.4: Detected FT232RL [160585.574534] usb 1-1.4: FTDI USB Serial Device converter now attached to ttyUSB1 No reboot required. Next I'll try to make up a little breadboard with the chip you suggest above and play around to see if I can get it to work. P1000 1 Quote Link to comment Share on other sites More sharing options...
Beat Posted March 18, 2021 Share Posted March 18, 2021 I had my communication board grilled when I connected simultaneously the Axpert(Synerji) RS232 and the Batteries BMS RS232 communication lines to the same computer. I found out the hard way that their ground references have about 10V difference. I would need an opto-isolator on at least one line. Actually I use 2 different laptops. In order to prevent spikes or radio interference to enter the devices I equipped the lines an both ends with ferrite cores. Quote Link to comment Share on other sites More sharing options...
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