Good USB RS485 interface?

[nctnico]

I'm a bit stuck between a rock and a hard place. I have a serial device which I need to operate using an RS485 interface instead of a regular full duplex serial port. The problem is that the device starts to send data back right after it has received the last byte so the RS485 bus has to switch from transmit to receive really quick. The RS485 adapter I'm using uses the RTS line to control the RS485 transmit but that lags behind a few ms. Does anyone know an RS485 interface which has some intelligence onboard to switch the RS485 quicker?

[David_AVD]

If you use the FT232RL it has a Tx enable line to run out to your MAX485 chip.  Not sure what the turnaround time is exactly though.  Has to be better than using RTS.

[IO390]

http://www.kksystems.com/

KKSystems have some good stuff if that helps.

[mikeselectricstuff]

Yes - FTDI chips do it properly - shouldn't be an issue with turnround time - I use them at megabit rates.
FTDI make a number of USB-485 boards,. and Easysync (part of FTDI)  do several cased products based on the FTDI boards.

[nctnico]

I have several FT232 boards lying around. I just never thought FTDI would be so clever to make their devices suitable for RS485 out of the box.
Thanks! 

Edit: I modified one of my FT232 boards and it works like a charm (with an external RS485 transceiver). I just ordered some FT232 based RS485 converter boards through Ebay to have some in stock.

[Monkeh]

Yes - FTDI chips do it properly - shouldn't be an issue with turnround time - I use them at megabit rates.
FTDI make a number of USB-485 boards,. and Easysync (part of FTDI)  do several cased products based on the FTDI boards.

I would not order anything from EasySYNC. Their website has been rather visibly compromised for many months now.

[mikeselectricstuff]

Yes - FTDI chips do it properly - shouldn't be an issue with turnround time - I use them at megabit rates.
FTDI make a number of USB-485 boards,. and Easysync (part of FTDI)  do several cased products based on the FTDI boards.

I would not order anything from EasySYNC. Their website has been rather visibly compromised for many months now.

In what way?

[Monkeh]

Yes - FTDI chips do it properly - shouldn't be an issue with turnround time - I use them at megabit rates.
FTDI make a number of USB-485 boards,. and Easysync (part of FTDI)  do several cased products based on the FTDI boards.

I would not order anything from EasySYNC. Their website has been rather visibly compromised for many months now.

In what way?

Scroll down to the bottom of their front page.

E: Okay, now I'm beginning to wonder. I know my machines and router are secure, and yet I don't see that over 3G or a proxy. I think I shall investigate further.

E2: Clean machine, at my modem. Still there. Cannot see via 3G (Three), tunneled to Germany or America, friends on BT connections.. See attachment. Time to phone my ISP.

E3: These should load and look suspicious for everyone: http://easysync-ltd.com/amnuthspely/so-now-you-know-a-bit-about-us-ckoqbkwelqmj.html http://easysync-ltd.com/amnuthpapserm/share-on-email-print-odontogenic-lesions-overvie-strepe-riplock.html

I will stand by my suggestion to be wary at this time.

[Quiggers]

Web site looks clean from here, none of that rubbish at the bottom like in the image you posted.

Can anyone tell me if
http://www.easysync-ltd.com/product/590/usb2-h-9004-m.html
appears as multiple com ports or as one com port?

Anyone have any experience of these?

http://www.advantech.com/products/5754ec6c-de46-4543-ab4e-f2a8d3e96c9c/pcie-1602/mod_00018e92-1b31-42e8-a930-9b3a2af8de2c

[Monkeh]

Web site looks clean from here, none of that rubbish at the bottom like in the image you posted.

Indeed, I've only ever seen that through my previous ISP. And yet, the link I posted still works from anywhere.

[mikeselectricstuff]

Web site looks clean from here, none of that rubbish at the bottom like in the image you posted.

Can anyone tell me if
http://www.easysync-ltd.com/product/590/usb2-h-9004-m.html
appears as multiple com ports or as one com port?

Anyone have any experience of these?

http://www.advantech.com/products/5754ec6c-de46-4543-ab4e-f2a8d3e96c9c/pcie-1602/mod_00018e92-1b31-42e8-a930-9b3a2af8de2c

Multiple port boxes appear as the corresponding number of ports. 16 port  boxes can take a while to install drivers....

[Quiggers]

Thank you Mike.

[bicc1306]

Web site looks clean from here, none of that rubbish at the bottom like in the image you posted.

Can anyone tell me if
http://www.easysync-ltd.com/product/590/usb2-h-9004-m.html
appears as multiple com ports or as one com port?

Anyone have any experience of these?

http://www.advantech.com/products/5754ec6c-de46-4543-ab4e-f2a8d3e96c9c/pcie-1602/mod_00018e92-1b31-42e8-a930-9b3a2af8de2c

I don't had any experience with them. I am a beginner in circuit board industry and most of times I have listen is all about pcbway and pcbshoppers.

[Delta]

Do you only have the one device on the bus?  I was looking for a PC - RS485 interface for a multidrop bus, but even after speaking to various manufacturers, I could not find one that supported 9bit mode...

[mikeselectricstuff]

Check the FTDI programming guides to see how/if their chips support 9 bit modes

[ebclr]

Take a look on this product


http://www.icpdas.com/schp/schp/detail.php?module_no=I-7520A