Choosing a PLC Brand... 3

[cfordyce]

I am replacing an old TI-500 series PLC ('87 vintage). I am having trouble deciding on a PLC Brand to go with. Whatever brand I choose will become the company standard for future PLC applications so I must evaluate each line carefully.

The TI-500 is simply monitoring RTDs, T/Cs, Discrete Contacts (Field Alarms), and a few process pressure readings (4-20mA). The PLC does no control... there are NO output cards on the rack. But there are 376 INPUT points. The PLC is interfaced to a PC (RS 232) where FIX SCADA software is used to indicate out-of-range readings and alarms, etc. The software interface is very rudamentary right now... just a text-based array of field points in a chart on the screen, when one alarms it lights up red and is printed to a log file for history trending.

I would like to replace this software with a more current graphical interface. I have the process flow diagram which I would like to be the basis of the software screen.

Does this sound like something that I could program myself with a current SCADA package or even just a HMI software package? Or would you suggest that I have this done by someone else (I do have other projects/responsibilities)???

Who would U suggest for this??? What software would U suggest??? Any suggestions on a PLC Brand?

I have checked out KOYO series from Automation Direct... but they don't seem to have the support base up here in Canada that they have in the States... but I like the prices.. and the extensive WEB presence, etc.

P/S. I am in Ontario, Canada.

Thanks for any input here folks.

 

[jlada]

In southern Ontario (as i am) the Koyo/Direct camp has less support than in the US of A. This is TI stuff which seems to have a greater following south of the border (too bad really, i enjoy the 'stage' programming myself). You'll find less support than either A-B or Omron which are considered the established leaders here. Either line has it's strengths in certain areas - A-B being easier to use for floating point calculations while Omron is generally considered cheaper, for example.

For this application however, the choice which of PLC becomes almost moot. Since you are into data collection only, you should be concentrating on SCADA programs. I have used the above mentioned Wonderware on large and small projects and enjoy working with it. It will talk to virtually any PLC or network but, the cost tends to spiral out-of-sight because of their 'tag count' definition. We have recently decided to tie into the National Instruments line for both SCADA and control (with caveats) wherever feasible. They have extensive lines of both hardware and software to choose from - all fully integrated. In this case, remote IO drops on a 'field net' protocol of sufficient speed to capture your quickest signals would be my choice. NI's Lookout for the data collection is just one possibility here. This would allow you to remove the entire cabinet and network (read rats nest) of hard pipes that this thing must surely look like...

;-)

 

[elec7]

WOW, how many people here have sold A-B before? The only good way to install an A-B is to wire one in, call the local Rep and chain the software guy to the machine. Don't unlock him until the machine performs flawlessly at the customer's site. Then prepare yourself to pay the oversized invoice!!!
I think with 300+ inputs and zero outputs you don't have to worry about "run-aways" and such.....I think a PC and E-net system would do.
The graphical interface can be upgraded and changed at management's whim and the reporting activity clearly shown in a touchscreen of your own design and layout.
Now...if in the future, your Company wants to control the machine here and there with a few added options(outputs)....KOYO/Direct is cheap, Ohmron is nicer and to be fair; A-B is reliable when you have it up and running. There is the software license cost to consider; that also shows up and the point-of-no-return$$$ in the design cycle!!! Good luck-G

P.S. I agree with almost everyone in this thread, it realy depends on your application.....and the future!

 

[cwkirby]

Be aware that AB is offering their 10 I/O MicroLogix (1761-L10BXB) for $99, and a limited edition RSLogix starter to program it as a free download. Having worked with both the SLC / Micro controllers, I'd lean this way rather than the Pico controller (also from AB)since the Pico's programming is very unlike other AB software.

 

[bbartson]

THE PLC VS PC CONTROL...
The PLC and PC-based Control both have their place in industrial automation. If the application is very low IO count, minimal HMI (Human Machine Interface), a very harsh environment where the controller must be mounted, or there is a very tight budget for the controls then the PLC is a great choice. If the application involves some fairly sophisticated HMI, database interface, data handling, data acq, complex algorithms, motion control, serial devices or 'fieldbus style' IO devices then the PC-based system makes sense.

I work for a PC-based control software company. For the last 8 years I haven't seen anything that a PLC does which the PC could not do. I have seen some cases of mis-applying the PC but I've seen lots of cases where somebody chose to go the PLC route and it would have been a lot easier to use a PC (with the 'right' software of course).

Let's all get over the religous arguments and take a rational approach to determining what is the right tool to solve the problem at hand.

 

[kenhnsy]

Thank you for the explosive topic. I have just been through vendor selection for a major greenfield plant. I recommend any 61131 compliant machine that links up via OPC. This is direction PLC's are going as they become a commodity. In the near future you will be able to replace anyone's controller with another just like you may do now with relays. And you have your choice of 7 languages. We chose ABB for various job specific reasons.

I hear that Automation Direct is now producing CPU's that will fit into their competitors' backplane and become 61131 compliant. That is where I would look first for economy.

 

[TravisWolfe]

From all the babble you can tell that no one person has the be-all-end-all solution. I have been doing this type of thing for many years and found that the simpliest way is the best way. Don't forget the overall point of the project. Unless you are looking for expansion capability and glossy looking graphics that tell you the exact same thing that the DOS look alike did, then stick with the basic systems. Allen Bradley surely has what you need...both inexpensive options and the overkill if wanted.
There are others available, as you have now found out, which could also do the job. Experience would be the best to rely on.

Why build a $100 MM gas plant to debottleneck, when buying a bigger valve and opening it will do the trick!

Good luck, need any help, let me know.

 

[cfordyce]

Well folks, I haven't been back to check posts in a while... Wow, hit on a hot topic here. For your info I went with Automation Direct. DL405 series PLC with an ethernet base controller instead of the CPU, I also found that the Terminator I/O (remote I/O) offers Thermocouple inputs for half the price of the DL405 T/C cards.. saved another $5Gs there at the last minute. I have the Lookout Direct software as well, and with all the money I saved from my project budget, I threw in a new $3000 laptop computer to make the development process that much easier.

I have been playing around with the Lookout Direct Demo software for a few weeks now and it looks like I should have an easy time of it once I get going.

I am building a development/training kit with a 4 slot DL405 rack, the remote I/O devices, some push buttons and pilot lights, etc all in an alluminum case (similar to a sales person's typical product demo setup. The bonus here is that these parts are not wasted.. they will serve as my spares when the project is completed.

If there is anyone in Ontario, with some experience with a similar project and who could be of some help if needed, I would appreciate an email address.

Thanks everyone for your input.

 

[skills]

Making a choice for Direct Logic speaks well of your judgement. I own May Techniques and teach automation seminars. I install and use about 14 brands and am amazed
at how AB persists in the marketplace with all the good choices out there. By the way a MPU is cmos not TTL as someone here suggested. What do people think a plc is. It is simply a specific function computer which is, at times, a preferable choice to custom building an embedded control.
Any I show people how to disconnected the SLC500s and put them in boxes. I believe this to be the most important skill one may have with these. Direct Logic appears to be superior to AB in every way I have ever cared to measure. I know of no one who has ever made the case for using AB other than, "I like the Salesguy or that is what my cousin uses". You can do anything with a DL240 or DL250 that you can with a SLC500 faster and easier. Anyone who needs any help with any Direct Logic products, feel free to holler at me.