USB to Serial (Good, Bad, Ugly?)

[Ken Roach]

I use Quatech PCMCIA serial expansion cards, which are pretty much the gold standard in the business.

They work great with DF1 protocol, but still do not work with the 1747-PIC/AIC+ driver. Nothing but a built-in RS-232 port will work with that driver.

I have been using a cheapo USB/RS232 interface this week.. it has a "Prolific" chipset but the vendor didn't think enough of the product to even stamp their name or part number on it. I bought it at Fry's Electronics.

RSLinx DF1 Autoconfig doesn't work on it, and every time I move it to a different port on my USB hub I have to re-install the drivers.

My recommendation remains to use a Keyspan USB/RS232 interface for everything except the RSLinx PIC driver.

 

[JesperMP]

In previous threads it looks like some people have succeeded with a combination of PIC and PCMCIA serial adapter.
Like HERE and HERE .
Though it doesnt look like it is a reliable solution.

 

[Progger]

serial

Hello, you can use also a PCMCIA to serial adapter.

Greetings

 

[jonny311]

My company bought an "iConcepts" USB->Serial converter (not an Apple product) with the Prolific chipset...I think it was pretty cheap. This converter does NOT work with GE VersaMax PLC's, by the way, which kills us. It does, however, kind of work with the AB SLC 5/03 I'm working on right now (we get wireless inet in this plant...pretty sweet). The problem is, I lose communication speed and throughput as the day progresses. At PLC startup, downloads are fast, but they progressively slow down and I periodically lose connection with the PLC. Anybody have any idea as to why? Is it something in COM config?

Jon

 

[JesperMP]

At PLC startup, downloads are fast, but they progressively slow down and I periodically lose connection with the PLC.

When something like that happens, it sounds to me like a memory leak. If it is in the driver to the Prolific USB cable, then there is not much you can do about it, apart from disconnecting and reconnecting with regular intervals.

 

[gluca]

I am anxious to see if the RS-232 port on the 1747-UIC adapter from A-B will function more like an on-board serial port when used with other (brand) devices.

Hello Eric,

did you try the 1747-UIC using it with other brand PLCs?

 

[Ken Roach]

I can stop that speculation: the 1747-UIC only works as a DF1 (USB) to DH485 (RS485 or RS232) converter. It does NOT work as a general-purpose USB to serial converter. Save your time.

 

[Greg Dake]

I can stop that speculation: the 1747-UIC only works as a DF1 (USB) to DH485 (RS485 or RS232) converter. It does NOT work as a general-purpose USB to serial converter. Save your time.

Almost as if it were a sin to get some functionality other than intended from an AB product...

 

[gluca]

Thank you Ken.

So at the moment which possibilities do I have to connect with a MicroLogix 1000 without a Real Serial port on my notebook? Do I need to buy a 1747-UIC or are there other choices?

 

[JesperMP]

The DF1 protocol used by the ML1000 is one of the least problematic to use with USB to serial converters. Probably any USB to serial converter will do.

Note: There is a version of ML1000 that supports both DF1 and DH485. If it is set to DH485 protocol, you need a 1747-UIC.