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USB adapter for PMC-8


r_hoskin@...
 

Jerry,


I finally pulled the trigger on an EXOS-2/PMC-8.  Just waiting on it to ship now.  I will be using it with a laptop.


I want to make sure I'm picking a serial-to-usb adapter that a) has the chipset you're recommending, and b) has good/reliable build quality.


I think the Startech ICUSB2321F checks boxes for chip, general reputation, and serial connector gender.  I did wonder if the serial port speeds were ok - looks like the Startech unit tops out at exactly the speed you are running the serial port at. I'd feel better if the adapter had some reserve capacity over what the PMC-8 uses, but perhaps I'm worrying over nothing.  


What say you?


Thanks!


Bob

 



hubbell_jerry@...
 

Hi Bob,  thanks for your decision to buy a PMC-Eight system. I looked at the adapter you have specified on this webpage:  https://www.startech.com/Cards-Adapters/Serial-Cards-Adapters/1-Port-USB-Serial-RS232-Adapter-Cable~ICUSB2321F and it should do the trick. The chip it is using is the pretty much the same one in the adapter I use from Parallax: https://www.parallax.com/product/28031.

It's interesting that the one you picked says in the spec that the baud rate is limited as you said to 115200. I expect that if it uses the generic FTDI driver, you can set the baud rate higher, but as you suspect, it might not be reliable That is not the case with the Parallax adapter. Also the one you picked on the webpage I found is $10 more. You didn't say how much the one you found was, but you shouldn't have to pay more than $20. If you are still deciding, I would suggest you get the Parallax one.

Thanks again, I look forward to hearing about your experience with the EXOS 2 PMC-Eight and be sure to contact me if you have any questions.

Jerry Hubbell
Director Electrical Engineering
Explore Scientific, LLC.



r_hoskin@...
 

Thanks, Jerry!

I'll hunt up a Parallax unit.  If you're happy using it and it has a better spec, that's what I'll use.

Google tells me that they are not that common up here (Canada), and that border puts us in our own world as far as pricing and availability goes (particularly for niche items), but I'll dig something up.  

- Bob



r_hoskin@...
 

Done.

But... on closer inspection, that little board looks a bit vulnerable.  I think I should come up with a case of some kind to give it a bit of mechanical support (and maybe weather protection).

Did you do anything to protect yours?

- Bob


hubbell_jerry@...
 

Hi Bob, it does look vulnerable, but I have used my open like that (it does have some clear heat shrink around it to keep the components safe). It has never been a problem. I am sure you can find others using the FT232RL chip that is fully enclosed also for around $20.

Jerry Hubbell
Director Electrical Engineering
Explore Scientific, LLC.


r_hoskin@...
 

Just FYI,  for any Canadians lurking...  

This unit isn't all that common up here, took a bit of hunting, but I did find the Parallax USB-to-Serial adapter on-line at Robotshop.com in Mirabel, PQ.  

Seemed to be reasonably priced for this side of the border, compared to other alternatives, just under CAD$41, with Expresspost shipping, for this item only to Ontario, plus taxes.  YMMV.  



David Pickett
 

At 18:12 13-10-17, r_hoskin@... [ESPMC-Eight] wrote:

But... on closer inspection, that little board looks a bit vulnerable. I think I should come up with a case of some kind to give it a bit of mechanical support (and maybe weather protection).
I just ordered one of these: https://www.amazon.co.uk/gp/product/B0758BMXBG/ref=od_aui_detailpages00?ie=UTF8&psc=1

It SAYS the FTDI chip is included and, looking at other models, it seems that the pcb involved could fit inside the housing of the RS232 plug. If true, it looks less vulnerable than the Parallax board. Similar devices must also be available at Amazon.com.

I will report here in due course whether it works or not!

David


hubbell_jerry@...
 

Should work okay.

Jerry Hubbell
Director Electrical Engineering
Explore Scientific, LLC.