Allen Bradley compact logix series A or B?

Good morning,
Im looking to replace some PLC's with the comapct logix series. either L23E, or L32E. These will be stand alone PLC's, but in the near future, will be controlled from our operator room via produced and consumed tags. I tried searching, but couldn't find anything that related to these particular controllers My question is about the difference between series A and series B on these controller modules. Anything inparticular you can forsee being a problem? Would it matter if one was series A and one was series B? if one failed and I replaced an "A" with a "B" and re downloaded a program? Thanks in advance, the help is much appreciated.

Also, does anyone have any experience buying a "factory sealed" unit off of ebay from China? Anything to look out for? I know we would all just assume support our local distributor, but sometimes we can only spend so much money..

Second post: Be careful buying stuff like that. Also a factory seal can be imitated. There are many examples on the forum here of people getting what they pay for.

If you are trying to save money, I would look at gently used instead. But that's just me

Turns out we have a tech support contract with AB. After talking to them, The only difference is a physical hardware obsolescence of ethernet parts. Should be interchangeable without issue.

I agree on the gently used parts.. The seller on ebay seems to have a good reputation, but I'm still a little bit leery buying things directly from China. Im sure some have had good experience, but others have had very bad experiences. I will keep my eyes open. Thanks for the response.

Handcraftedsince87 said:

Turns out we have a tech support contract with AB. After talking to them, The only difference is a physical hardware obsolescence of ethernet parts. Should be interchangeable without issue.

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This is not 100% Correct!

Series A accepted Firmwares 13 - 20 where as Series B only accepts Firmwares 16 - 20. Now if your using version 16+ then yes they are interchangeable without issue, but if (like us) your using version 15, you have a problem! We ended up moving to Version 20 and tweaking the program a little bit to get the same performance.

Regards
Ian

Well that's good to know. That was all the technician from AB had to say. Luckily, we are running v19. Thanks for the response.

Handcraftedsince87 said:

Also, does anyone have any experience buying a "factory sealed" unit off of ebay from China? Anything to look out for? I know we would all just assume support our local distributor, but sometimes we can only spend so much money..

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99.99% of the stuff coming out of China at prices too good to be true, "factory sealed" or not, is counterfeit. No ifs, ands or buts. They are experts at not only counterfeiting, but faking things like "factory seals" and "original packaging", whatever buzz words they need to include to get your money from you. There is zero recourse against them, so they can act with impunity and suffer no consequences.

Siemens got hit hard by that a few years ago, fake Chinese counterfeit PLCs started showing up all over the world from China. They were absolutely worthless junk, flooding the Tech Support system Siemens had in place. Siemens started recording the serial numbers of the counterfeit units (many of which were the same, because they didn't really care) and if you called in to get help, they insisted you give them a valid serial number. If it was on the list or even just out of place, as in you are calling from the US and the S/N was assigned to units originally shipped to Turkey, they would make you prove your point of purchase before answering your call. A-B records all serial numbers as they are sold to their authorized distributors. I don't know for sure if they are implementing a similar thing when you have a Tech Connect contract, but I would not be surprised. It's a serious problem for mfrs.

have you ever looked at plccenter.com
I have picked up quite a few items from them, mostly older obsolete Omron units when we had some equipment to fail and had to have it back on line very quickly

Its not that the prices were that "too good to be true".. They seemed fair, just that the units were in a more "factory new" condition. Like I said, I have always been a little leery buying straight out of China, but have never before been burnt on a unit purchased online..yet. The only thing that gave some solace is that it looks like they have been selling parts for a while and have a good amount of positive feedback for these types of transactions. I am in need of 3 L23E units, and between ***********.com, and PLCcenter.com, they have 2. Knowing now that they don't need to all be the same series makes finding them a little easier and probably not worth resorting to buying this unit from China. I know we usually all get what we pay for, and I'm OK with that. There seems to usually be an acceptable middle ground when buying new Allen Bradley parts isn't an option. Just thought there might be a recent rash of counterfeit AB stuff coming in from China that I didn't catch and would be worth poking around a little.

Thanks again for all the input from everyone

Handcraftedsince87 said:

...Luckily, we are running v19. Thanks for the response.

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Yes, but v19.xxx <what?...

Just watch your minor firmware revisions as well...

There are 15 firmware revisions available for the 1769-L23E. Of those, the series B L23E only supports 4.

For the L23E, firmware revision 19 is available at three different minor revisions...

V19.011 <<<Series A L23E only
V19.013 <<<Series A L23E only
V19.015 <<<Series A or B L23E

The Series A L23E supports revisions 17 - 20 inclusive.
The Series B supports revisions 17 - 20, but not inclusive.
The Series B only supports v17.012, V19.015, V20.013, V20.014.

As for Chinese "merchandise" and East v West...

An old Chinese proverb..."Nothing is too deceitful in war".

Regards,
George

I guess this is where I start to get a little confused with AB revisions. The version we are running is 19.01.. can't I use any processor with firmware in the 19.xx?. As far as the firmware revisions of the L23E, more specifically the 1769-L23E-QB18, not the L32E, Im not sure what it will ship with as it will most likely be a "gently used" controller, or a Factory New, Surplus stock

Also, when I look at the f/w updates from AB.com it lists the same versions for both series A, and series B.

20.014
20.013
20.012
20.011
19.015
19.013
19.011
18.012
18.011
17.012
17.007
17.005

depending on what version this "gently used" processor comes with, shouldn't I be able to use a processor with either version A, or version B and flash version 19.015 (if it doesn't have either .013, or .011) and program everything with RSLogix v19.01?

Handcraftedsince87 said:

I guess this is where I start to get a little confused with AB revisions. The version we are running is 19.01.. can't I use any processor with firmware in the 19.xx?. As far as the firmware revisions of the L23E...Im not sure what it will ship with...

...shouldn't I be able to use a processor with either version A, or version B and flash version 19.015 (if it doesn't have either .013, or .011) and program everything with RSLogix v19.01?

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Yes, of course you can. I'm sorry if it sounded as though I was stating otherwise.

The advice you received from RA is correct. The Series B L32E and L23E controllers were only released late 2013 due to component obsolescence related to the Ethernet hardware. However, what they failed to inform you of is that only specific firmware revisions support the new Ethernet hardware components on the Series B controllers.

This is what I was/am informing you of, nothing more.

A scenario I had pictured...

You are using RSLogix 5000 v19.01.

You have a Series A L23E using firmware revision 19.011.

You know this because you have taken note of it.

You want to replace it.

You order a second hand Series B L23E.

You don't know what firmware revision the second hand L23E will have upon delivery.

It arrives and it has firmware revision v17.012.

You want to match the original firmware revision v19.011, to keep it as identical as possible.

You cannot flash it to firmware revision 19.011.

You can only flash it to firmware revision 19.015.

You might wonder why not?

You might not wonder at all?

That is all.

When flashed to firmware revision 19.015, the Series B L23E will be fully compatible with RSLogix 5000 v19.01.

My point was not that you will loose any functionality, or compatibility with RSLogix 5000, but simply that you cannot match Series A and Series B L23E firmware revisions like for like. I was more pointing out a subtle difference, not easily spotted, and obviously overlooked on their download site. The FRN they have listed as available for the Series B is incorrect. Only the four FRN I have listed above are compatible with the newer hardware. In fact, originally, they released the Series B of these controllers with a sticker on the front, stating that you must use FRN 19 or higher. They then back tracked and also made revision 17.012 compatible. Unless they have since back tracked and done some of the others, they should not be listed.

Here's a Technote on the compatibility of FRN for all CompactLogix...

521476 - CompactLogix Series and FRN Compatibility Tables
Access Level: Everyone

Regards,
George

Ok, what you said makes sense now. Thank you for the clarification George, it is greatly appreciated. If i was going to flash new firmware I usually would do the latest minor revision possible, however I see how that could throw up some ?? without knowing. Glad to be aware. You learn something new everyday!

It's possible you are purchasing counterfeit products, but more likely that you are simply purchasing products that have been re-sold in violation of their distribution agreement.

Global companies like Rockwell, Omron, Schneider and Siemens frequently use pricing as a competitive tool depending on the market. In markets where their brand is weaker, they use lower prices to grow market share. In China, all the multinationals are competing for market share, so you can buy PLC hardware cheaper in China than almost anywhere else.

It's impossible to say if these eBay sellers are authorized distributors who are violating their distribution agreement, or companies whose business involves buying high-value electronics at a discount and reselling it outside the region it was intended to be sold.