Tied up serial port issues

[ianbuckley 0]

I have been getting hit by complaints from customers about communicating via the serial port. The problem frequently involves having RSLinx installed on the PC using typical installation (which loads RSLinx automatically). The customer then goes to communicate to a different device (motion, HMI or other PLC) over the serial port, and can't because RSLinx is pigging the port. The customer assumes the problem is with the software other than the one causing the problem (RSLinx). We have been giving instructions to show people how to run RSLinx with manual launch instead of Auto, to mixed results. <Understatement alert> Not all plant electricians are as clever and savvy as the ones who visit this site. I was wondering if any of you have found a utility somewhere that would let a different program use the serial port when RSLinx is loaded? It could either share the port with or take control of the port from RSLinx (or some other program for that matter). Thanks for any help.

[Sleepy Wombat 27]

For AB i just copy the following bat file onto my computer and create a short cut on the desk stop... StopAB.zip

[TimWilborne 108]

Also, the serial driver in RsLinx can be configured as On Demand or Manual instead of Automatic

[paulengr 44]

RS-Linx Enterprise is even worse. It hides out as a service and you can't even tell easily that it's running. And there's no "on demand" mode.

[Crossbow 295]

I see this all the time, and we typically change the RSLinx setting to Manual. Stupid that AB takes ownership of the serial port like they're going to be the only thing on the PC, but that's the arrogance that is AB. No method I'm aware of other than the ones mentioned, which are stopping the offensive RSLinx service.

[gravitar 3]

To each their oen I guess.. It's kinda funny how us A-B guys that have just recently had to start using Siemens software (thanks GM) frequently complain how the Siemens software infects your entire computer like a virus!

[Crossbow 295]

My point was that most PLC vendors only use the port when their programming software is running, or even only when you try to go online. But RSLinx takes ownership as soon as it's installed. For people in the field supporting many vendors' equipment, it's an extra step, and usually i install it, use it, then uninstall it when done. That way it's not there to interfere.

[PdL 71]

I always use this tool to change my COM port arrangement.

[Sleepy Wombat 27]

(Both you guys have made me crack up LOL) Lets all revolt and change to OMRON ....

[TimWilborne 108]

Or Ethernet?

[OZEE 5]

Or USB? Why aren't there any PLCs with USB ports yet...????

[Mickey 71]

There is ControlMicrosystems for one. SCADAPack Series http://www.controlmicrosystems.com/ Edited 17 Jul 2007 by Mickey

[PdL 71]

Like Sleepy says... Omron CP1H:

[TimWilborne 108]

Maybe it's just me, but my thought is if you are going to get a communications port, why not go ahead and get one that could be later hooked into a network for data acquisition? USB is extremely limited on distance.

[OZEE 5]

Good point. But if I have one that I'm going to want to hook into a network for any reason, it's going to have a protocol available that will support that (Ethernet, DH+, Modbus, ...) I was thinking of the small, one-off, isolated machines that we all have, and the increasing difficulty in finding a notebook with a real serial port. Wasn't aware of the Omron with a USB. (but we're all AB...)

[PdL 71]

I think cost is involved here. Although you can get any PCI Network adaptor for $20,- for most PLC's an ethernet unit or on board ethernet port costs big $$. I guess a USB port costs about as much as a SUB-D serial port. But I agree life would be a lot easier if all PLCs have Ethernet by standard.

[DanW 41]

The serial comm port monitor software download http://forums.mrplc.com/index.php?autocom=downloads&showfile=605 mentioned by PDL in the 2nd post on this thread is a .rar file. Is this a Windows file? How does it execute as .rar? Dan

[TimWilborne 108]

It is like a zip file. You need a utility such as Winrar to unzip http://www.download.com/3000-2250-10007677.html

[panic mode 246]

just a note on USB, Mitsubishi flagship (Q series) comes with both USB and RS232 on each CPU (only exception is the lowest model, i guess they killed it on purpose just so it doesn't compete with more expensive models).

[TimWilborne 108]

I don't think it is a matter of cost when it comes to USB vs Ethernet. I think it is more a matter of preference and design. Some might say USB is simpler because you can just plug the cable in and windows will automatically configure the drivers Others may say Ethernet is simpler because it is a more universally accepted network and is likely to be around for a long time. I don't want to start a flame war here but you can buy a Micrologix 1100 with an Ethernet port for less than $425. I think this is about the same price as an Omron CP1H. My point isn't that one is better than the other, but one has a USB port and the other has an Ethernet. The price of the USB interface vs the Ethernet interface must be insignificant for both of them to cram so many good features into these models and not leave these interfaces off

[panic mode 246]

usb is simpler to use for people not familiar with ethernet addressing for example cabling is (more or less) standard and it's faster than RS232... RS232 only doesn't have the speed (nobody bothers to go past 19.2 or 38.4k on PLCs and HMIs even though RS232 is good for much more than that). personally i like ethernet, you can have multiple devices talking to each other, fast, cable length is not much of an issue (hate retainer clips, metal version connectors like for profinet are more sturdy but keep on opening, this fast connect is ok if this is not moving but once you throw the cable in a bag, it's different story), one can easlily and cheaply buy new cable (or make own). usb has the mentined limitation of cable length, only peer-to-peer connections, limited selection of cables (try to find 6" USB cable with connectors you want when you need it) which makes use of pass through bulkheads more difficult (sure you can use 6' cable inside and outside but longer cable inside cabinet adds to the length, just another constrain). i've also seen some issues with USB, certain devices are very picky about bulkheads, and don't work at all while everything else seam to be quite happy with it. also many USB devices don't work properly if they are plugged in before PC boots connected when power is applied so for example one may have to plug and unplug USB cable every time PLC is reset for example etc.

[Sleepy Wombat 27]

Funny, I run my HMI talking to an Omron PLC at 57k...and i connect locally via toolbus at 115k... sure fast enough for me ....

[PdL 71]

Well Tim, as long as our TS ianbuckley doesn't continue reply to his topic I think we can hijack it . For all the good reasons to switch to Omron, pricing wouldn't be your main reason. Cost is involved, definitely with Omron. I used Omron247.com to look up some prices (excellent website btw), and see what I mean: CJ1M-CPU12 $462.28 (CPU without Ethernet port) CJ1M-CPU12-ETN $845.63 (same CPU with integrated ethernet port) The Micrologix 1100 is about 1/2 the price of an average CP1H CPU. But, I think the CP1L which is the light version of CP series comes closer to it. Dedicated ethernet card for CJ1/CP1 series CJ1W-ETN21 $917.38 I never really understood these absurd pricings for this piece of hardware against like I said $20,- for a PCI Ethernet adapter. For all I know they are manufactured at the same plant, perhaps some more reliable hardware components but it is no rocket science anymore right I agree on you I also can't really see the "BIG" advantage of USB over serial and definitely not over ethernet, as Sleepy says with Omron CS/CJ series and NS HMI serial means 115k which is fast enough. OK it is simpler to use (for 1:1 connection) like Panic says but there it ends. Now I must admit I haven't used any USB CPU yet so I might turn around but I don't think so. With HMIs it is good to have USB as then the speed over max serial speed gets interesting with big file transfers.

[ianbuckley 0]

Hijack away! I figure the longer the thread keeps showing up in "view new posts" the better! It's an interesting debate in any case. Doesn't really influence my issue, because these customers have machines in the plant using PLC5 and older SLCs, which only have serial connections. For updating progress of the original thread, I have found a couple of utilities on freedownloads.com that have wonderful testimonials from people using GPS systems, but they didn't seem to work with the applications I was using (RS Logix 500 and a few different small motion controllers and specialty PLCs).

[Crossbow 295]

Mitsubishi has USB ports on most of their PLCs, newer HMIs, latest servos, and high end VFDs.