plc3 to plc5 program conversion

[nileshsurya 0]

hi there, will anybody please tell me the procedure to convert an allen bradley plc3 program logic to plc5 program logic it will be very helpful for me thanks in advance nilesh

[Guest Guest]

You are probably going to have to find a systems integrator that does PLC-3 to PLC-5 conversions. I don't believe a conversion utility exists, like the one for PLC-2 to PLC-5 conversion.

[mgvol 0]

Javlyn, Inc. (www.javlyn.com) specilaizes in PLC-3 to PLC-5 conversions.

[Ken Roach 194]

I agree, converting PLC-3 to anything else is a manual operation. Although Javlyn and Rockwell Automation both have utilities they developed in-house to do the grunt work, there are no simple conversions to PLC-5 or ControlLogix that don't require a lot of labor. Don't just get a contractor who assumes they can do PLC-3 because they can do PLC-5. Get either RA themselves or a contractor like Javlyn who knows what they are doing.

[rcastellanos0523 0]

TRY SOFTPLC www.softplc.com IT WORKS VERY GOOD...AND NOT EXPENSIVE......BELIVE ME I KNOW.....

[Gerry 13]

At this point in time, replacing a PLC-3 with a PLC-5 seems a pointless exercise. Both processors are obsolete. You should be thinking about ControlLogix. A CLX processor is most likely cheaper today than a PLC-5. It will support your RIO and DH+, if that is a concern. PLC-3 systems tend to be large - will a single PLC-5 have enough I/O capacity and/or memory? It's more likely that a single CLX processor will.

[Eddie Willers 2]

I don't think a SoftPLC or any other brand is going to be the best fit, Raul. The PLC-3 system is likely running A-B Remote I/O chassis, and might even be a redundant hot-backup pair. No other control brand will let you re-use that 1771-series I/O, and SoftPLC's hot standby doesn't support A-B I/O chassis. PLC-3 conversions are a big investment in engineering time. I probably quote one every couple of months, but have not sold many because I get customers who have a tiny fraction of the original controls budget to do the retrofit, and they usually add a big stack of features they want to add to the controls, while maintaining all the original I/O and wiring. ControlLogix has been my platform of choice. It gives me more options for new features, like adding Ethernet or DeviceNet or Profibus. The big gotcha has been making sure that there is enough CPU resources to handle a lot of old-fashioned Remote I/O, especially with large numbers of analog modules. This is why guys who make PLC-3 conversions a speciality win a lot of business, and guys who only dabble tend to make expensive oversights.

[mgvol 0]

While the PLC-5 is older technology, it is not yet obsolete! In fact, according to AB's Silver Series (old stuff being put out to pasture), the only part number listed in the 1771 line is the empty slot filler. Far from obsolete.

[Gerry 13]

The PLC-5 may not be officially obsolete, but you only need to look at the pricing of PLC-5 (and 1771 I/O) vs CLX to get a picture of AB/Rockwell's true sentiments. Why replace the PLC-3? Most likely because it's obsolete and spares getting expensive or hard to find. Why go through an expensive conversion to something that will require another conversion for the same reasons in 2-3 years?

[mgvol 0]

No, I don't...1771 I/O has always been more expensive than other lines/brands. Partly because of its rugged construction: I know of a PLC-5 installation where the rack/modules have about 3/4" of salt caked on them and it is going strong after 11 years. Bulletin 1336 AC drives are ~25% more expensive than a comparable PowerFlex, but that doesn't make them obsolete. The installed base of PLC-5 is so large, and in some installations so complex, that many can't afford the hardware/engineering and downtime costs associated with changing to ControLogix. ALCOA, in some of it's plants, are currently looking at converting their PLC-3's to PLC-5's and then onto CLX in 4 or 5 years. We sure did spend a lot of money advertising the PLC-5 this year, if they are obsolete!

[Gerry 13]

In the immortal words of your avatar, " This show's getting silly" Forget the brand issue - just look at the price history and you will see that the PLC-5 has escalated significantly in recent years. The PLC-2 and the PLC-3 went through the same sort of escalation before becoming officially obsolete. You will also note that the escalation only starts when there is a new product designed to take over the particular market sector. And please don't think I'm impugning the PLC-5 in any way - or the PLC-3 either. I've worked extensively with both as well as CLX. I'm not advocating wholesale conversions of running systems. But when an owner decides that the age of his system poses such a significant risk to his operation that he must replace it, why not opt for current technology? What is the benefit of replacing 25-year-old technology (PLC-3) with 20-year-old technology (PLC-5)? I note you said "We", so I guess you're an AB/Rockwell employee. In spite of any advertising, I don't believe that anyone seriously promotes the PLC-5 or 1771 I/O for new work.

[Ken Moore 23]

Not having any experience with the CLX line. I always assumed a new CLX processor could be installed and still use the 1771 I/O via RIO adapters. Is this incorrect? I currently have a large production line that is run using three maxed out 5/80E's, with LOTS and LOTS of analog I/O. The 5/80's are maxed out in memory (huge ladder files, lots of block transfers) not on amount of I/O. I had planned on looking into replacing one of the 5/80's with a CLX to get more memory capacity. But it sounds like my plan isn't viable, should I consider adding an additional 5/80 instead?

[mgvol 0]

Yes, can use the CLX processor w/1771 I/O thru a 1756-DHRIO module.

[Ken Roach 194]

Since the original poster has not replied to this thread, I don't feel too bad about hijacking it to discuss ControlLogix and 1771 I/O. There are "gotchas" when replacing a controller with a large 1771 I/O system with a ControlLogix. Because Logix controllers are built around CIP networks like ControlNet and EtherNet/IP that take care of configuration and data transfer invisibly to the user, they don't have as much ability to handle RIO Block Transfers as the PLC-5 and PLC-3 do. A Logix controller can, for example, handle just 16 "cached" block transfer instructions. If you have more than sixteen analog I/O modules in the 1771 system, you're going to have some trouble with that. It doesn't matter how you split up the I/O among DHRIO scanners; this is a CPU limitation. You could go "low and slow" and just use uncached connections to get your analog I/O, but that requires more programming discipline and is lower performance. Going to ControlNet doesn't gain you much; even though the ControlLogix supports discrete 1771 I/O on ControlNet, you still have to use CIO instructions to set up the analog modules and get analog data to and from them. There is a specialty module that can be used with the ControlLogix to accomodate large RIO networks. It's called the 1757-ABRIO and is configured with a separate utility to handle large numbers of racks and large numbers of block transfers. Data is then brough into the ControlLogix via CIP explicit messages. The right solution for upgrade depends on the scale and I/O mix of the original system. Fortunately, the Forum is a big place !

[Gerry 13]

My apologies if I gave that impression - see my first post in this thread. I have minimal experience with the DH/RIO module so can't offer any info on how well it works when highly loaded and/or performing lots of block transfers. I'm sure you're aware of RIO's one block xfer per adapter per I/O scan regimen and may have your analogs clustered in the local processor chassis. If so, replacing the 5/80 with an ASB will seriously degrade update times for those analogs. Might be better in this case to off-load the logic to CLX and retain the 5/80 to gather the analog data. The ethernet protocols are different on PLC-5 and CLX, but I think they can work together. I see Ken got in ahead of me: I had a suspicion there were limitations - couldn't remember what they were Edited 6 Jan 2005 by Gerry

[Ken Moore 23]

Thanks for the 1771 I/O with CLX clarification. I have way more than 16 analog cards per PLC, so I'm going to investigate all my options. How difficult is it to pass data back and forth between PLC-5's and CLX via ethernet or DH+? I currently use ethernet for the HMI and programming, and DH+ to pass data between processors. Since I'm looking to expand versus replace, perhaps adding a CLX system for the expansion would be best. However, it would have to communicate with the 5's, not a lot of data, something like 20-30 words per PLC. Each 5 handles a section of the process, but passes status and permissive words back and forth.

[Gerry 13]

It involves programming MSG instructions - not terribly different from the PLC-5. However, I think all comms would have to be initiated by the CLX If you are doing significant process control with the analog data, I think you will really appreciate the CLX's function block programming.

[Ken Roach 194]

A technote showed up today regarding large amounts of RIO with ControlLogix, which includes some updated information about buffers and caches and so forth: Knowbase A105731474

[Ken Moore 23]

Thanks Ken, The tech note was just what I needed. Ken

[Guest Doug_P]

A PLC-3 to CLX conversion is in our future here. All six controllers contain a GA-BASIC modules, connected in turn to 1771-RM's to handle the interface to an RFID tag system. How is the BASIC conversion normally handled in this type of conversion? Thanks

[Gerry 13]

There's no direct equivalent to the GA/RM in CLX. However, the point I/O RS232 module operating over Devicenet or Ethernet/IP might be close. You would have to handle any string manipulation in ladder or structured text.

[Guest Doug_P]

Gerry, Thank you. If somebody gets an idea to do this in-house, I'm going to do all I can to discourage it - I know they'd look at me and I don't relish converting 6 ea. ~3K rung programs. Luckily, the only data involved is a 4-digit numeric ID retrieved from the tag.

[Jabercrombie 0]

Just to correct the statement on CLX BT's it is 32 block transfers per controller max cached and 16 per channel on the DHRIO card that is what you get into with large 3's but I just did a large plc3 system and used a 1756-RIO card and the card does all the BT's which allows much more throughput and it will run in shadow mode where you can hook it up with a scanner and run your app before putting it online which helps debug it before you shut the system down. The plc 3 is a power house and if you have a lot of 1771 I/O it is best to just change it over to clx I/O and be done with it as it makes a lot better system and is so much easier to program....Most PLC 3 programs use a lot of binary and hex lots of or and & nand gates with file bit compares and file search compares that you have to write the logic for as there are no conversions for them. The one I just did had 8000 rungs in only one routine which made it a nightmare to convert.......