Panel USB and USB to serial converter

[rockber]

Hi engineers,

I have to communicate with an AutoSampler, it has a RS232 Virtual Com port vía USB. This serial-usb converter is a FTDI chip, so here are my problems;

Trying to communicate trought- PANEL USB and cable directly. It does not work, i always recived -1 on status Tx. i was looking for any information about this and I have seen that Unitronics recommend Profilic converter but this AutoSampler has installed and FTDI , how can i communicate with it directly, like on my PC, with my PC i can send commands via terminal and everything works properly.

[Joe Tauser]

The Unistream does not have a driver for that USB converter; it's not like your PC where you can load one in.  

Does the AutoSampler have any other communication ports?  It may have been designed to only operate in a PC environment.

Joe T.

[rockber]

Thanks for your reply Joe,

The autosampler just has a single type B USB port. I will ask to the autosampler supplier about a prolific converter in autosampler instead ftdi one installed already.
I’m thinking to put something like a bridge ( imagine from USB unitronics-prolific232converter-prolific232converter-USB to connecting Autosampler usb port. Could work? I will test this idea tomorrow.

An other idea could be installing UAC-02rs2 comm module and connect directly a Prolific232 usb converter and connect it to autosampler port.what do you think?

thanks for all your info,

BR

 

[Joe Tauser]

I'm afraid that without the proper USB driver none of these solutions will work.  The PLC has no idea what's connected to it in that little USB box.

You need to get something with a real RS232 port.

 

Joe T.

[Ausman]

I"m no expert, but it's likely the sampler only has the FTDI chip to "make it easy to connect to with something that doesn't have a 232 port". 

On this basis, could you get into the PCB to get the older serial stream that is going into the chip, and access it directly with a bit of hacking.  Lots of mucking around, but perhaps not as  hard as it first seems.  So many things these days have "USB ports" when in fact they're simply converting old serial data for "user convenience".  The manufacturer pretends it's "modern" and has had a huge change, but in fact it's the old thing simply fitted with the converter.

cheers, Aus

[rockber]

We can not modify the sampler pcb, actually we are working with unitronics support trying to find any solution.

If we can not find a software solution, we will implement a raspberry as echo device. Receiving commands from PLC and sending throught other port to sampler, could be work i guess.

Thanks for your info, i'll update with the solution given finally.

[AlexUT]

It depends of PLC model and firmware version.

Unitronics added FTDI and Silicon Labs support.

Drivers added to use with barcode readers (check  "Enable USB for HID Device").

In your case check "Enable USB for Serial Device".

Test it and share results.