AB vs. Omron

[blueheeler 0]

I have been asked justify buying AB when the software cost is so much higher than Omron. Can anyone give me anything to justify the higher cost of Rockwell's software? And if we were going to base the purchase totally on cost wouldn't PLC Direct be the better choice? I believe the PLC Direct hardware and software is less expensive.

[Nathan 7]

To what extent are you asking about hardware versus software? AB makes top notch hardware. Fans enjoy the reliability, company commitment, and programming feature sets - and it's ex-pensive. I wouldn't say the same about their software in general except about the price. Besides the programming application (RSLogix) you're free to use other brands of software. I like PLC Direct. I've never heard anyone claim that the hardware is better than AB. Their PLCs run lots of facilities without problems. I've spoken to several integrators who swear by them and other who will only use AB. Does the quality justify the price discrepancy? I doubt it. It's brand snobbishness versus value - choose what you will. My prediction is that the gap will close plus the little guy has the option to do better things like include way more memory and processing power on their cheap lineups as technology improves. AB doesn't have the same luxury as they need to maintain a steeply tiered pricing model. The only PLC Direct software I've used is the programming software. I can't speak to the Omron question.

[panic mode 246]

try another platform and see if it works for you... (you make saving by the end of the year)

[TConnolly 13]

There are other things to condisder besides the initial cost as well. Look at your local support infrastructure. If you have good AB local tech support and the local distributor is on the ball, but brand X local support sucks, then it may very well be worth it. OTOH, if the local AB distributor is a bone head and brand X has good local support then, capabilities being equal, pick brand X. In our case the local AB distributor knows their stuff, they stock all the different processors, racks and most of the IO modules, and they have several on staff who deal exclusively with PLCs and software, and there is a local AB office as well - no other PLC maker rivals their support, or even comes close, in this area. But I know that is not necessarily true in other places.

[Nathan 7]

Good point. Beyond tech support, stocking inventory is huge when something goes wrong. It's unlikely to have spares of everything on hand. Cumon guys, grow some and answer OPs question as to the general quality between brands. I favor the TIAS advice in general, but we don't have to pretend that they're all identical. That's a bit like recommending that a car buyer test drive a Kia versus a Honda to evaluate reliability. Edited 29 Apr 2008 by Nathan

[horthek 0]

I use PLC Direct hardware for small appications such as running the lead lag time for compressors locally, self contained blower applications, etc, anything that doesn't require much developement time. For process control I always use AB. The developement time is much less than any other PLC application in my opinion and if you use RS View for a front end the integration is seamless and quick. I use Omron exclussively for motion control. I know, I know, AB guys here are gonna puke but I believe Omron does a much better job of stepper control, I believe their steppers module to be a tad faster and easier to set up and implement. However, I love Allen Bradley. For support, stocking distributors, ease of development (Control Logix mostly).

[paulengr 44]

Most of Omron's PLC's are oriented towards "machine" applications...ie, you put their PLC's everywhere all over your plant. The AB PLC's are more oriented towards "process" applications...you'd have just a few PLC's controlling huge sections of the plant. They also have more or less direct support for motion control if you want to do high end motion control (servos) and want to write your motion control logic directly in the PLC. If it's the case that you essentially only need programmable "smart" relays, you can always use AB's pico PLC's which have free programming software. That's most of the applications I see Omron PLC's getting used for anyways. There are some "reduced" versions of AB's systems. For instance, the motherlode is RS-Logix 5000 Full and concurrent. But that costs nearly $5,000. In contrast you can go for a "maintenance" version at about $500 a piece (view and set forces, but no programming), and if you go for the CompactLogix processor, you can get by with lower end licenses that are closer to $1000. If you are working with Micrologix processors (which are much more akin to most of Omron's PLC's), then at least one version (check the FAQ on this board) is free. In my case, we only have a few PLC's but we have lots and lots of distributed I/O (in the neighborhood of 10-30 nodes per PLC). Programs occupy hundreds to thousands of lines of code. A lot of it is math-based (analog). I shudder to even think of trying to do that with lower end PLC's. A better comparison would be between AB PLC's and GE's PACS series. That being said, I'm a bit partial to Modicon (Telemechanique) that you didn't even mention. Those processors can be less expensive than AB and their remote I/O is both ubiquitous and very low cost.

[panic mode 246]

imho this was very appropriate feedback.

[Nathan 7]

That was great feedback. I guess I didn't format my responses clearly compared to what I was quoting. I was supporting Alaric's comment. My first paragraph was supposed to go with the first quote and my second paragraph with the second. I responded Edited 1 May 2008 by Nathan

[panic mode 246]

never mind. can you please tell me what TIAS stands for?

[rdrast 3]

Try It And See Or, if you don't like that, googling "Acronym: TIAS" comes up with some others... TIAS--Target Identification & Acquisition System TIAS--The Internet Antique Shop TIAS--Treaties and Other International Acts Series (compendium of treaties, United States) TIAS--Treatment Indicated with Aspirin & Statin (medical treatment of transient ischaemic attacks) TIAS--True Indicated Air Speed (aviation) TIAS--Try It and See (chat) TIAS--Telematic Internetwork Abstract Service Edited 13 May 2008 by rdrast

[panic mode 246]

thank you