There seems to a functional difference between USB serial adapters that have a UART and those that those that do not. The same applies to PCMCIA and Xtend cards which often act like USB adapters for this purpose.

Sorry, I do not know why this is true, but I know from experimenting with them that it is. I'm doing OK so far with an adapter from SIIG. You could also look at National Instruments and Sealevel.

 

Going forward, of course, the rational thing to do, considering that others are deciding for us that we no longer need the serial port, would be for PLC manufacturers to simply include a USB or Ethernet programming port. The right way to do it would be to have it isolated etc., so that we can use a widely available cable and no ridiculously expensive adapters or one-off plugs or any of the other pure and avaricious BS they try to palm off as necessary.

There is really no excuse for their "special" connectors or non- standard hardware when the cheapest (by virtue of volume) and best (by virtue of utility) solutions are OTS commodity items. It can't possibly cost more to integrate commodity silicon for these ports than any contrived non-standard and the connectors are proven and foolproof.

As for the current situation, there is still an adequate market to support serial ports and nothing on the current machines really adequately replaces them. I have yet to see a 1000' USB cable and Ethernet to serial conversion isn't too great except in certain circumstances. I think the denigration of serial ports is, at least in part, an assault on character-based devices in general to solidify an all GUI vision of the world. But there are still far too many things that RS232 and friends do best to simply write them out of the picture. I still believe that these folks that are scrambling for solutions simply bought a laptop that doesn't meet their needs. And whose fault is that? It should be a deal breaker when offered a machine which lacks basic necessary functionality for automation. Why do it, and deal with even more headaches when having to support five versions of Windows and DOS and many generations of shrinkwrap software? Isn't it about time this market becomes user driven rather than vendor driven? If people simply say no and follow up with their checkbook, I assure you this will change. There are many laptop vendors who would be very pleased to have all the automation and field service business simply by keeping their serial ports. There are machines for much smaller niches than that. Most of the crappy aspects of automation are with us simply because people accept them. The smallest amount of organization, agreement and cooperation could change any aspect of this market.

Regards
cww

 

One among many technical reasons to dump Microsoft. There are choices written by techies for techies that are superior in every way for automation. And support for the user side is now very competitive. All we have to do is make the right choices and stand up a little. We are buying a multi million dollar press that is automated with Linux, RTLinux and a few other RTOS bits. Obviously, if the automation vendors won't change their stripes, they can become irrelevant. Clinging to MS after they become actually detrimental to automation (Vista?) isn't going to fool everyone forever.

Regards

cww

 

Hi,

Omron's new CP1H PLC does have a USB port. This is the way forward.

Rgds,
Gabriel

 

In reply to Curt Wuollet: You've raise a number of detailed points about how things ought to be done which I will deal with in turn.

Curt Wuollet: "the rational thing to do... would be for PLC manufacturers to simply include a USB or Ethernet programming port."

MG: Ethernet would be much preferred over USB for PLC programming ports. Many PLCs already have this, and it allows flexibility in accessing the PLC remotely or over a network that just isn't practical with USB. USB might be suitable for connecting things like bar code readers (especially hand-held ones) or label printers.

Curt Wuollet: "have it isolated etc., so that we can use a widely available cable and no ridiculously expensive adapters or one-off plugs"

MG: I believe that Ethernet is already transformer isolated. And yes, anything other than standard plugs and cables would be foolish. To go directly from a PC to a PLC CPU without a switch you would need a cross-over cable, but those are still standard even if they are not as common as straight-through cables.

Curt Wuollet: "It can't possibly cost more to integrate commodity silicon for these ports than any contrived non-standard and the connectors are proven and foolproof."

MG: This is more or less what Siemens said in their product seminars when they introduced the Ethernet based Profinet to replace the RS-485 based Profibus. Note that Profinet is still a proprietary protocol (even more so than Profibus). The decision to use Ethernet was based on cost, not on any intention to be "open".

Curt Wuollet: "I think the denigration of serial ports is, at least in part, an assault on character-based devices in general to solidify an all GUI vision of the world."

MG: No, I think its just a lack of a consumer market. USB really is better than RS-232 for connecting flash drives, cameras, and music players. It is much faster, and can provide the power for things like flash drives. Another advantage is that most of these USB devices emulate a disk drive, so you can just plug them in without installing any special drivers. The old cameras which used RS-232 were a pain, because they all used different proprietary drivers.

Curt Wuollet: "There are many laptop vendors who would be very pleased to have all the automation and field service business simply by keeping their serial ports. There are machines for much smaller niches than that."

MG: They're usually pretty expensive too.

 

You will need a USB to Serial Convertor. There are too many standrad convertor cables available in market. However this will work only if the PLC programming software which you are using is Windows based and not DOS based.

 

I just bought a Dell Latitude 520 that has a serial port. I also have tried USB-232 adapters, and the only ones that I have not had any issues with are the Edgeports, which are carried by B&B Electronics.

 

The most common Siemens S7-300 PLC's have had built-in Profinet/Ethernet ports for a couple years that can be used for programming or networking I/O.

 

HP still sells a Laptop with a real serial port
Model: NX6320. At least in Australia anyway.

 

Yes it is powered by the USB port.

 

It also wouldn't hurt to provide some basic functionality with public/Open protocols so integrators could communicate with the devices without being or paying a member of the Profibus club or other cartels. Being able to map a block of registers with TCP/IP packets would go a long ways towards being able to integrate systems with a few lines of glue code rather than an enormous monolith. ModbusTCP would be one way but if that's politically unfeasible, a simple x registers per packet with a checksum would suffice. Of course, once you can map registers, you have most of the magic of SCADA so I expect that to be expensive and complicated for a while yet. And this simple proto over ethernet would outperform most proprietary offerings, causing more paranoia among the bean counters. If people understand how close they are to having really useful and universal hooks for integration, they might get cranky with the hoops they have to jump through now. It would be truly trivial to provide this kind of thing, only the cash cows stand in the way. But that will pass, or PLCs as we know them will become irrelevant. All the broken or crippled forms of ethernet devised for cow protection will pass once they coexist with anything Open. Open protocols for automation simply make too much sense.

Regards

cww

 

Hi,

We've had the same problem, but there is a solution... Dell Latitude 620/630 and the 820/830 series still have the "forgotten" serial port. Just go to dell.com and check it out yourself. We just bought 2 630s and the serial port works with old DOS applications. Even the old Siemens S5 PLC software works with it!!

Tlynyrd
(ytsejam prog-rocks-solid)

 

Try the serial converter from this site: http://www.serial-converter.com

Steven

 

I have a Dell Latitude with serial port, I purchased it from the Rockwell vendor to run RSLogix5000. I had the vendor load the software but found it extremely slow. I sent it back and they zapped the OS and reloaded regular XP professional. It's much faster. Apparently the Dell version has so much C*** included.

Hope this helps someone.

Roy

 

Just found another usb/rs232/rs485/rs422 converter from this site: www.usb-serial-converter.com. Vista, Mac and Linux supported.

Steven

 

Dell Latitude 5510 has a serial port on it still.

 

A new small Ethernet serial port device is this one: http://www.icpdas-usa.com/products.php?PID=3611

You will need either a switch/hub/router or just an Ethernet cable (crossover or straight) to connect it to a laptop. For Windows machines, a virtual com port allows applications to access the nine pin com port.

 

If going for USB to RS232 - best to go for one with FTDI chipset. FTDI is very good with Windows 7 64-bit drivers also. Some machines don't need CD either - the OS just support it including Linux.

Try http://www.tronisoft.com/2455.php

There are other places but usually much more expensive.

 

The Dell Latitude e5510 is the best.

 

>Dell Latitude 5510 has a serial port on
>it still.

You can get a E-Legacy Extender for all newer Dell Latitudes if you need a serial port

http://accessories.us.dell.com/sna/...etail.aspx?c=us&l=en&s=dhs&cs=19&sku=430-3115