Where Is Eric Nelson When You Need Him?

I have a cable problem! Actually it is a laptop problem.
We got a new Toshiba laptop and when we went to the plant the other day to hook up to the Modicon Compact 984 we discovered that the new laptop has no serial port. Is there a way to build one compatible with the USB? If so does anyone have a pin out?

I've seen some cables advertised that look like they might do the trick but it might be a little more fun to build one and save the $50.

I'm here, but can't help you with this one....

There are plenty of guys in this forum with answers about which USB to serial adapters work/don't work with which PLCs. Personally, I'd use a PCMCIA (PC Card) to serial adapter, though these have their own issues.

Blame the guy who spec'd the new laptop.... Why did they get one without legacy ports?????

Good luck!!!

-Eric

Who knows what powers the brains of the guys in the carpeted offices. We gave the specs and they said No Problem. Then when we got it we asked where was this, where was that? The usual questions... They reply was that this was a good deal and you did not need all that stuff anyway. Then the serial port! Something we were very specific about! The reply to that was "This is a problem?" Don't get me wrong, I love my AC in the office but these guys really should try to leave their offices from time to time and get a look at the real world.

Oh my I guess that was a sore subject, sorry. Anyway, thanks for the help big guy. I did find a great source on the USB from one of the old posts last night and I am going to try and see if I can prove to somebody in the carpeted offices that I really need it and the exact one that I specify. May the gods of purchasing smile on my req.

Thanks again!
Derek

Derek,

FWIW, one of my customers was in a similar situation a few years ago. Their IT department had put some strict specs on what computers could and could not be purchased, what OS they they had to have, what software had be bundled with them, who had administrator privileges, etc.

The maintenance department needed a new laptop for programming their PLCs, but they knew that the IT Dept. specs would render the laptop incompatible with some of the PLC software they needed to run.

The solution was to have me, their PLC vendor, purchase a laptop and resell it to them as a 'PLC Programmer". It helped that the Purchasing Manager was feuding with the IT Manager at the time.

working for me so far

You obviously missed my previous post. Here is a cut and paste. Definetly works for Modicon, haven't tested with a SLC yet.


My former Problem: I originally found problems with newer computers and going online with the Modicon Micro via the Serial port. I am running Windows 2k and when I would work online, the connection was very slow. Plus, certain tasks like search and online editing didn't even work.

My Solution: I found this USB serial adapter from Keyspan (www.keyspan.com) part number USA-19QW that has fixed the problem. When I go online with the Modicon Micro now, it is super fast. All my former problems have disappeared. Plus, now I have a free serial port to connect to the HMI.

I don't know how much it costs since I found it in the desk drawer of a former employee that was using it with XP, but I think it is about $60.00.

P.S. If anyone knows what the actual cause of the problem is, or if there is a plain windows work around, that would be cool to know too.

I didnt miss your previous post, and made some suggestions. Try it with the SLC (especially a PIC) if works you are ok. If not go back and look at other options/suggestions I posted.

Steve Bailey said:

Derek,

FWIW, one of my customers was in a similar situation a few years ago. Their IT department had put some strict specs on what computers could and could not be purchased, what OS they they had to have, what software had be bundled with them, who had administrator privileges, etc.

The maintenance department needed a new laptop for programming their PLCs, but they knew that the IT Dept. specs would render the laptop incompatible with some of the PLC software they needed to run.

The solution was to have me, their PLC vendor, purchase a laptop and resell it to them as a 'PLC Programmer". It helped that the Purchasing Manager was feuding with the IT Manager at the time.

Click to expand...

Yeehah! I need a new "portable email access tool."

Hey I read it last night! Seek and ye shall find. However, I tried something different with the next part. Knock and the door shall open... It was more like knock and the drawer will open.. Problem was we don't have any former employees that left any of those cables in their drawers.. But thanks mucho for the information in your post of problem solved! I have become freinds with a fellow who just happens to work in our IT department. He has been promoted recently and has remarkable purchasing powers! I handed him the information from your post this morning and he assured me that covert ops would take care of it. Life Is Good!

Yeah, its a good idea to get friendly with the IT guy/gal. In my case it happens the IT guy use to have my job. Whats so unique is I know his job as well as he does(I was/am an OEM for computers), he comes to me for info. I give it freely, makes my job easier(when I need a computer related item) and I doubt he will be replaced by anyone any time soon, unless he decides to leave.

I wish there was a message icon for "running around screaming with hair on fire".

The one thing you won't be able to use a USB/RS232 converter with is the 1747-PIC/AIC+ driver in RSLinx. That driver is tricky enough with a classic 16550 serial UART chip, but putting the USB layer and redirector software in the middle makes it impossible.

I have not had a USB/RS232 converter fail to work with DF1 full duplex protocol, and I've used four or five brands; Quatech, Belkin, Keyspan, etc.

You'll find them in retail stores now; I bought six Belkin units from Fry's in a hurry for a Logix 5000 class when I found the rented PCs had no serial ports. Those were a little flimsy, with a too-big transparent plastic shell. The main plus is that they were fun to take apart to examine the FTDI chips inside.

I prefer the one B&B Electronics sells, mostly for it's small size and indestructible potted polyurethane shell.

My best guess with the Micro 984 is that the "real" serial port is a little weak on voltage levels (maybe a power saving thing) and the USB converter is a little more standard !

Yeah Ken, I saw the same one a few months back at Fry's. I was on one of my trips to Dallas to face Meca uh, Frys, and I saw them. I was tempted to pick it up but was not sure just how well it would work so I balked. Now that I have my covert op guy in IT things are going to be much better.

I can't thank everyone enough for their input.

Derek

Doesn't the whole world know that Modbus protocol depends on timing (character times) to determine when a packet start and stops?

Doesn't the whole world know that USB/serial adapters buffer characters thereby changing the timing between characters/packets because the USB/serial adapters doesn't know where the packets begin and end?

At least Modicon users should know this.

Obviously the IT guy was LACKING in the 'I' part of IT. I would hold this over his head the next time a decision like this had to be made.

Get a Dell Inspiron 8100. They are great for programming. Inspirons 8100 have 1600x1200 pixel screens, a serial port and Ethernet port.

DF1 works over USB because DF1 does not rely on timing during normal packet transfer. The USB adapeters do slow DF1 down.

We have found that USB/serial adpters slow down PLC serial protocols. Moving window protocols, such as ZMODEM, would not be affected as severely.

Well it has been my experience that The Whole World as you say does not apply to IT. In the minds of IT you are in there world and there are no other worlds than IT. If you talk to someone at IT about PLC's most get a very strange look on their face.

The first law of IT is that the perfect network has no users.
Users are stupid and have no reason to request something from them that they don't understand. If they don't understand it, you don't need it. I am fortunate now that I have a friend in IT now that I have lured over to the Dark Side. Boo Haw Haw Haw Haw... Sorry that was my best evil laugh.

Derek

You mean that there are other ways to send data besides ethernet? -IT Guy

Rick! There certainly are other ways... There's the European Swallow carrying packets in the coconuts tied to their feet. No, I mean the the South African Swallow. AAAAAAAHHhhhhhhhhhhh....

I wish I were a lumberjack.