Best choice to replace an old A.B. 2/02 PLC

[milmat1]

I need to replace an AB PLC.
Its an older 2/02 that has only
2 X 16pt 120VAC Input cards (1771-IAD)
1 X 16pt 120VAC output card. (1771-AOD)

Which Allen Bradley platform would be best here. I was thinking of using a SLC setup like this:

1746-A4 chassis
1746P2 pwr supply
1746 L514 Processor
1746 IA16 Input cards
1746 OA16 Output card

Is the SLC a Good choice here ?

 

[jkerekes]

CompactLogix. Why go through the conversion effort and then go to a platform that's at the end of it's life?

 

[milmat1]

IDK That's why I asked, And I know very little about AB / compact logix.

I'll have a look at them...

 

[jkerekes]

OK. Then you're at the right place to ask questions. CompactLogix hardware is now cheaper than most SLC stuff.

 

[Bit_Bucket_07]

OK. Then you're at the right place to ask questions. CompactLogix hardware is now cheaper than most SLC stuff.

I understand it costs less, as well.

 

[Brijm]

I wouldn't put a new SLC in, as others have said, they have been around for quite some time. CompactLogix also seems like overkill for this project.

I would look at one of the MicroLogix series, Probably 1400

 

[TConnolly]

Either a MicroLogix 1400, or a CompactLogix.

Check out the new 5370 Compact Logix controllers.
The 1769-L24ER-QB1B comes with 16in and 16 out built in and lists for $1860.* You'll need to add expansion IO. CompactLogix controllers require RSLoigx5000 software to program.


A Micrologix 1400 has 20in and 12 out and lists for $830.* You'll need to add expansion IO if all of the PLC/2 IO is being used. You'll need RSLogix500 software to program it. There is a version of Loigx500 that only programs the Micrlogix line and it is very inexpensive.

A Micrologix 1100 has 12 in and 6 out and lists for $630.* It only supports four expansion modules but that's enough for you. Depending on your true used IO count the ML1100 might cost a little bit more, but the ML1100 can be programmed using the free version of Logix500.

*The prices are list prices. Your actual prices through a dealer will be somewhat less.

Edit to Add:
Compare those prices with the lowest model SLC500 with ethernet (the CLX and MLX models above all have enet), the 1747-L551, which lists for $4470, and that doesn't include a rack, power supply, or any IO.

 

[jkerekes]

I wouldn't put a new SLC in, as others have said, they have been around for quite some time. CompactLogix also seems like overkill for this project.

I would look at one of the MicroLogix series, Probably 1400

That would probably be a good choice too. An 1100 might fit to with the small I/O. CompactLogix is more competitive than ever with their smaller units.

 

[Ken Roach]

If I were in your shoes, I would take a different approach than just "brand, I/O count, and price".

What sort of sensors does the controller connect to ? How many amperes do the outputs drive ?

Most of the small controllers from any brand use 24V DC I/O.

At 120V AC, your selection gets a little more limited. And the 120V AC outputs on a MicroLogix are going to drive less current than the 120V AC outputs (1/2 A or 1 A, depending on the module) on an old 1771-OAD module (2A per point, up to 8 A per module).

What is the application you are running ?

The first time I quoted a PLC-2 conversion job I was feeling good about it until the customer quickly accepted my bid, and I found out it was a burner controller and they expected agency conformance in the price of the PLC conversion.

Do you have any of the software tools for A-B controllers, or experience using them ? If you have a limited budget, you might get sticker shock when you see how much the software editors cost.

 

[bce123]

You could replace it with this. The price is right, pretty much just shipping and handling!

 

[Lancie1]

BCE, What is that thing?

 

[The Plc Kid]

Looks like a plc-2 Mini.

 

[milmat1]

I wouldn't put a new SLC in, as others have said, they have been around for quite some time. CompactLogix also seems like overkill for this project.

I would look at one of the MicroLogix series, Probably 1400

Thank You !!

Either a MicroLogix 1400, or a CompactLogix.

Check out the new 5370 Compact Logix controllers.
The 1769-L24ER-QB1B comes with 16in and 16 out built in and lists for $1860.* You'll need to add expansion IO. CompactLogix controllers require RSLoigx5000 software to program.


A Micrologix 1400 has 20in and 12 out and lists for $830.* You'll need to add expansion IO if all of the PLC/2 IO is being used. You'll need RSLogix500 software to program it. There is a version of Loigx500 that only programs the Micrlogix line and it is very inexpensive.

A Micrologix 1100 has 12 in and 6 out and lists for $630.* It only supports four expansion modules but that's enough for you. Depending on your true used IO count the ML1100 might cost a little bit more, but the ML1100 can be programmed using the free version of Logix500.

*The prices are list prices. Your actual prices through a dealer will be somewhat less.

Edit to Add:
Compare those prices with the lowest model SLC500 with ethernet (the CLX and MLX models above all have enet), the 1747-L551, which lists for $4470, and that doesn't include a rack, power supply, or any IO.

WOW ! Quite a Difference Huh....Thanks!!

 

[brstilson]

SLC is at the end of its life. CompactLogix for a few digital IO points may be overkill.

I'm going to have to tentatively concur with the Micrologix 1400. You get ethernet built in, online editing, less than $1000, din rail mounting, you can't go wrong (plus I like that you can set the IP address on the 1400 via the LCD panel). Preliminarily, I'd say you'd need the following part numbers.

1766-L32AWA
1762-IA8 (x2)
1762-OA8 (x1)

NOW, before you order any of it, think about the loading of the outputs. What's the duty cycle? What kind of load is it (coils, lamps, etc.?) How hot is the panel? You'll really want to look at this because the 1762-OA8 is a triac output and is only rated at 0.25A at 55C (0.5A at 30C). I'm only guessing but it's not much of a stretch to assume the 1771-OAD triacs were probably rated at a higher current. One option might be to get a relay output card (1762-OW8 or OW16), BUT relay outputs have a MUCH SHORTER life than triac outputs. You're only talking about 2 million operations for relay outputs under the best circumstances. If your load exceeds the triac rating but you have a rapid-switching application, have the triac outputs fire an ice cube style relay, which has MUCH higher contact amp rating and much longer life than PLC relays. If you don't want to bother with all that, there's no shame in going to a CompactLogix.

But in either case, check your output loading and consider this when selecting output cards.

 

[TConnolly]

One thing that can be a strike against the ML1400 is wiring. Inputs wire into the top of the Micrologix PLC where they entered the PLC/2 1771 wiring arm from below. Your existing wiring might not reach around, requiring you to replace the wire. If you have only a couple of hours to make the switchover then the extra time this will require is a potential problem.