Will USB to RS232 Converter work??

ECSI

Member
Join Date
Jun 2002
Posts
4
I'm looking for a new laptop for programming PLC's and SCADA apps. The newer laptops are coming out without serial ports. Have any of you tried a USB to RS232 converter for PLC programming? If so, did you have any problems with it? I understand that the converter comes with software to create a virtual com port using a serial rs232 port...so when you specify a com port with your PLC software, it will actually redirect data to a USB port. The laptop that I want to buy (Toshiba) has no RS232 serial port...but I would make the purchase if I knew that this converter would work problem free. Thanks!!
 
... what it is doing is the OPPOSITE of working...

Maybe what we need is a thread where people post the OS, PC model, PLC model, and USB/RS232 model that they *do* have working.

You'll see here and in a lot of other threads (and boards) that results have been mixed. Particular to my business, I've been unable to get a 1747-PIC driver for RSLinx working in Windows 2000 or XP by any means except a built-in serial port. (USB is a no-go, and I haven't gotten PCMCIA-RS232 working).

That being said, I've used a number of USB/RS232 units successfully to communicate using Allen-Bradley DF1 Full Duplex protocol. Rockwell Software has documented a couple of USB/RS232 units from Belkin and Keyspan that work well with that protocol.

What PLCs and operating systems are you working with ?
 
Thanks to a late-night EBay binge last week, I became the proud owner of a UE-RA15SC-A USB/RS232 converter this morning. Fifteen bucks, how can I go wrong ? It's ten feet long and has a electronics bump halfway along that's the size of my thumb.

It took me a half hour of Google searching to find out the OEM is a Chinese company called WanTeng; they really like to paste "OEM" all over their stuff, and the documentation is lousy. Fortunately it's based on one of the popular FTDI USB chipsets, so they know more about it than the OEM does.

It wouldn't install correctly... Windows wanted to use the "USB.INF" driver instead of the one that came with it. That led to a "a function driver was not specified for this device instance" error message.

This may be my fault; this PC has had three USB/RS232 converters connected to it in the past, and I have been abusing it's registry and PNP setup to try to get a PCMCIA serial port working.

I uninstalled the drivers for all of the add-on serial devices I had, then rebooted... and PNP worked correctly. I have a COM3 !

I was pleasantly surprised to find that it correctly did DF1 Autoconfig to an SLC-5/05 serial port in Windows 2000 SP2; none of the other converters I've tried did that.

[later edit]
Now that I've gone back to it, I find it keeps getting re-detected as new hardware... I'm going to have to figure this out. :(
 
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alternative

Of course, you could always just buy a PCMCIA card with a serial port on it, then no worries, you have an rs-232 port.
 
Details

I'm using Windows 2000 OS, laptop model to be determined...probably toshiba. I program mostly Omron PLC's but would like to hear of any experiences with AB, Siemens, and GE also.

I've been told by a few people that PCMCIA/RS232 is not an option...it just won't work! Thats why I'm looking at the USB/RS232C options.
 
Hmm. Generally speaking, if a PCMCIA/RS232 port won't work, it's my experience that a USB port won't, either. That's certainly the case with A-B's 1747-PIC DataHighway-485 driver.

There's a good Omron discussion group over at www.MrPLC.com, with some real experts that might know about Omron family interfaces and ports.

Yesterday my laptop had four COM ports; COM1 built in, COM2 and COM4 from an 2-port PCMCIA card, and COM3 from the USB adapter. All worked fine with DF1 full duplex and ASCII.
 
The conventional wisdom around here says "don't try this one at home, kids." Very few have said that they've been successful with USB to serial devices. You can see from Ken's post what it usually takes to get things right.

Look at it this way:

You're trying to install a beast of a converter - USB to RS232
Onto a beast of an operating system - Windows
And you're using a beast of a protocol - PLC programming uses lots of messaging back and forth

Put three beasts together and you've pretty much created a monster. I think you're slightly better off with PCMCIA. The card slots are better at immitating what a PCI or ISA slot would do for you. That makes the new comm port "feel" more like a standard comm port when Windows or your programming software tries to get at it.

AK
 
I think AB and others will have to come out with USB versions of their interface cards. Such as a version of the AB PCMK card that will talk directly DH485, DH+, etc. Considering the obvious rising demand, it would be stupid not to. (Am I giving them too much credit?)
 
Hey, hey, hey.... enough topic hijacking. I want this to be about what works!.

There's a thread about USB and the PIC over at the RSI forum that hasn't gotten much play....
http://www.software.rockwell.com/forum/rslinx/messageview.cfm?catid=75&threadid=3453

AHEM. The "OEM" UE-RA15SC-A unit I mentioned above has some more miles on it now and I can give it only a mixed review.

When I power up with it plugged in, it works. When I plug it in after powering up, I have to go to Device Manager and remove/reinstall it. Yuck.

On the plus side, it does DF1 Autoconfig, a vital thing when you walk up to strange A-B PLC's all the time like I do.

And I have it working with the 1770-KFD by building myself an adapter cable that jumpers DSR/DTR together on both sides.

I feel like it's a little bit slower than DF1 with a built-in serial port. But it'll fit the bill when I need a serial port and don't have one !
 
I think AB and others will have to come out with USB versions of their interface cards. Such as a version of the AB PCMK card that will talk directly DH485, DH+, etc. Considering the obvious rising demand, it would be stupid not to. (Am I giving them too much credit

1. What does the PMCK card have to with USB interface?

2. When wont the PCMK card work with the above, assuming you have correct cables? At $1800 or so for the PCMK card, WHY make another version/device that does the same?
Excerpt from PCMK manual:?PCMK MANUAL
The PCMK/B card is a PCMCIA Type II form-factor card that allows a notebook computer to interface with other devices on both DH+, DH485, and remote I/O communication networks.

I have stated this before, the problem with no serial port is not JUST that its missing, the systems that dont incorporate one have issues that are not conducive to them...ACPI. This issue also creates problems with USB and in some cases PCMCIA cards..especially with devices like the 1747 PIC.
 
ECSI

I use Dell C800 with build in RS232 port and I have also PCIMCA port
both are work fine.
I use moat of my time Omron and AB.
The PIC is not working with the PCIMCA card. AB have USB to RS232 and PIC adaptor its call UIC.it cost about $250.I ordered one and wait for this over a month.
Pay attention if you want to work with AB you need fllopy drive for activation disk. I think it have to be build in drive.
The activation can work only from A drive (unless there is new solution).
CX-Programer work with most of USB adaptors but you need to check it by your self.I would go for PCIMCA it more safe.
You never know which software you going to program.
BTW I couldnt conect to NS touch screen with the PCIMCA adaptor.
only the build in port.

All the best
 
ArikBY:
1747-UIC is for DH485 only, it does not work for DF1 protocol.
AB just released a new USB-To-Serial converter (9300-....) for DF1 protocol.

Look at www.plccables.com for USB cables for some PLCs.
 

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