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Ab Slc 5/04

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I am a beginner and have no idea how to program a plc yet so please bear with me. We have a machine which use an Allen Bradley SLC 5/04 (1747-L542) Processor unit. I was having some issues with a couple of solenoids, so I was checking the wiring to make sure every thing was tight and connected when I accedentially pulled the Power Supply unit (1747-P2) out which cut the power to the processor and I/O's. Natural reaction was to push it back in and when I did I started getting a fault light on the processor blinking at me. I have tried to reset the processor by turning the key, to no avail. I have talked to AB tech and they said that I may have lost the program, and to get into the processor to see what the fault is. Problem is we do not have the Logix500 software, I do have the LinxLite to connect which it does. What can I do to find out what is causing the fault light so I can atleast know what I am up against? Thank you for your time My direct email address is ryan@heparrest.com

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Sounds like AB have hit your problem on the head, it is likely the program has been wiped, you need to get a tech in to sort out your system... Hope you have a backup copy of the code!

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I hope I'm not being overly optimistic, but I would like to believe that simply removing power from the rack wouldn't default the processor! I would put my money on the program still being there, but some minor fault condition exists that has to be cleared before you can go back into RUN mode. The bottom line is, as you've already figured out, if cycling power and/or flipping the keyswitch to program and back to run doesn't clear it, you'll need RSLogix. And like Snerkel said, hopefully you have a backup of the program!

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I have had this exact thing happen on one of my projects. It did in fact erase the program. It was a SLC5/05, but the program was gone. They had to pull me off the airplane to get me back to the plant. (That was fun!) Ever since then I always check the screws that secure the power supply to the rack.

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Pretty scary. I didn't realize pulling it out would do that. But the SLC does not support hot swapping so I guess that is one of the reasons why Just did a check on a SLC 5/03 and could find no way to get the error code with RsLinx Lite. It would probably be a good idea to call someone in. Preferably the manufacturer or the machine if they are local. I guess you did try cycling power to the PLC didn't you?

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I guess I had never though of removing power from the rack as a "hot swap", but then again maybe the power supply does something on power-down other than going *poof*. Oh dear, now I'm concerned.. Hot swapping in a 1746-chassis does BAD, UNSPEAKABLE things. Often characterized by physical damage to the bus transceiver chips on one or more components. (Really! When I was a co-op in the training department at Mac & Mac, whenever someone would complain that their SLC wasn't working, I'd pull all the cards out and LOOK for a cracked or split chip!) At least he's got a FLASHING fault lite, that almost always signals a recoverable condition.

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yep ... it tells the processor "hey, we're losing power ... start shutting down NOW!" ... the power supply then provides a few extra seconds of "hold-up" power while the processor does an orderly shutdown and goes to sleep ... without that orderly shutdown period, all sorts of problems may develop ... as others have said, you need to get someone out there who has RSLogix500 available ... and of course, hopefully you have a good backup copy of the program ... and depending on where you're located, sometimes shipping the processor to someone else is an option ... make sure that they have a chassis, etc. and a copy of the program handy ... they can download the program and then return the processor to you ... since the led is FLASHING (and not solid) chances are better than 50-50 that's all that you need to get things running again ... the downside, of course, is that if you're not particularly lucky these days, then you might STILL need to have someone pay you a visit anyway to dig a little bit deeper ... finally ... if you're not familiar with how EEPROMs work, it might be a good idea to research them ... having one plugged into the processor would probably have taken care of this problem - even before you knew that you had one ...

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You know, that would explain a wierd problem I had with a P2 supply I had a while back. It kept the rack powered up and happy all day (or week.. or whatever) long. But if you cycled power, it would power up to "DEFAULT"! Drove me crazy.. Swapped out EVERYTIHNG but the power supply with the same result. I was starting to think someone was playing a trick on me! Finally I tried the P/S as a last resort, and never had the problem again.

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Does this mean that my fault light might be caused by the power supply unit and not the processor at all? If that is the case would changing the power supply fix my problem? How would I check the power unit to see if it is a problem? Thank you Ryan

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Ryan, What this means is that you need to reset the fault in the processor. The cause of the problem was removing the power supply under power. This is what caused the fault light to start flashing on the processor. You will need RSLogix 500 and RSLinx to communicate with the SLC to clear the fault and a copy of the program to download back into the SLC. I hope this helps. swimmy67 Edited by swimmy67

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Update. I borrowed a computer with RS Logix 500 and ran it to see what I get. When trying to go online I get the following popup box _____ Default SLC Program Fault Code 0001h Default program loaded due to NVRAM error. A corrupt CRC was detected (loss of battery power mays cause this) or a powercycle in the middle of a user program download, initialize memory or memory module load Cannot go online or upload from default processor (no program). You must perform download OK or Load from EEPROM _______ When I click on Load from EEPROM, I get the following box ______ RS Logix Resource not available Memory module not present _____ What does all this mean? I assume that download means download from the PC to the PLC. In other words means that my program is gone, right? Thank you Ryan

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yes, your program has gone to "bit heaven" ... you must either (a) come up with a copy to download to the processor ... or (b) write a new one to download to the processor ... that thing about the EEPROM ... the message means that you don't have an EEPROM chip installed in your processor ... it's a plug in option that you didn't buy ... check around for a copy of the original program ... it should be a file that ends in .RSS or .ACH ... if you absolutely can NOT find a copy, check and see if there is a paper printout of the original program in a notebook lying around somewhere ... you'll still have to key it into the software, but it will probably be easier than writing the program from scratch ... good luck ... Edited by Ron Beaufort

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At this time I would like to thank everyone who has given me guidance and answers in my quest for PLC understanding, it is certainly appreciated. Just to update, I spoke to AB tech and they verified that the program is gone. I have the program in paper form and I was reading through it (more so flipping through it looking for something that I might understand) and I found in the Processor Config Report reference to a Flash EEPROM Size :512 does this mean that I have one or is that the max allowable for the board? Now some programing lingo that I don't quite understand fully The following is an example from the printed ladder | E-Stop Online | | Relay PB | | I:7.0 B16 |0,/2,4,5,6 |___|/|___________________________________________(U)___| | 13 16 | | IB16 | I understand that the E-stop relay is a description and is entered as follows I:7.0/13 but what is the IB16 ?? B16 I don't know how to write the (U) 16 Finally what is the 0,/2,4,5,6 ?? and how does it get to the other side of the ladder? Thankyou Ryan It is supposed to look like this with exception to the ...........'s which are ment to be spaces EXCEPT I7.0 |.E-Stop........................................................................Online..| |.Relay..........................................................................PB.......| |.....I:7.0.........................................................................B16...|0,/2,4,5,6 |___|/|___________________________________________(U)___| |......13.............................................................................16....| |.....IB16...................................................................................|

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the "IB16" is the type of input module that this particular input signal is connected to ... the "0,/2,4,5,6" is part of the Cross-Reference (X-Ref) listing ... basically it lists other rungs on which this same address is being used ... as for the "EEPROM yes/no" question ... take a look at the picture in this post ... it shows where the EEPROM would be physically located if you had one ... it's an SLC-5/03 in the picture - but that should be close enough to your SLC-5/04 to help ... I'll write more when I get a chance ... teaching this week and short on time ... question: how many rungs are listed in that printout you have? ... are we talking about 10-15 rungs? ... or maybe 500 rungs? ... Edited by Ron Beaufort

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Ron Thank you for your time in helping me. I have finally figured out that I do not have an eeprom, I was looking a another chip that looked very similar to an eeprom chip we have in one of our other machines. I reread my post from last night and I realized that the B16... should look like the following, not how it looked last night. B16 (U) 16 The program has 6 files with a total of 81 pages of ladder logic, the balance of about 53 pages include a cross reference report, Data table file report, Data table dump report, Data table usage report, Data base form, Unused address report, I/O parts list, Rack des. report, Revision history, Sequencer data report and Processor config report. I estimate that there is 5 rungs per page so about 400 rungs total. Thank you Ryan

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Greetings Ryan, here are some details about the bit address you've posted ... that bit can be addressed in either of two different ways: either as " B16:1/0 " ... or as " B16/16 " ... either way is perfectly acceptable ... look at it this way ... my name is "Ronald Howard Beaufort" ... but you can call me "Ron" ... the address B16:1/0 means that the bit is located in file number B16 ... and that the bit is located in word number 1 of that file ... and that the bit is number 0 within that particular word ... or ... the address B16/16 means that the bit is located in file number B16 ... and that the bit is number 16 within that file ... as I said, either method of addressing is perfectly acceptable ... and the software can be set up to display the address using either method that the programmer prefers ... the --(U)-- is an "unlatch" instruction ... basically it tells the PLC processor to "go write a zero into this box" ... typically it's used to "turn off" something ... I'm just wondering ... why are you asking about this one particular part of the program? ... it seems like you've got a lot of much bigger fish to fry ... as for your project ... I haven't seen your program of course, but my guess is that someone has about two days of steady typing ahead of them ... that's taking care of the documentation too ... of course some people are faster with a computer keyboard than others ... but I'd say that transcribing about 400 rungs and the associated documentation sounds like about a two-day job ... Edited by Ron Beaufort

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Ron, Your help is greatly appreciated. I am trying to wrap my head around the understanding of the program as this is the first time I have ever looked at anything PLC related, when I first looked into the controller unit I thought "OK well that looks nice" and shut the door, and now that the program has gone to heaven, I must retype the program in. As of right now, from the reading I have been doing and the information you and everyone else have kindly provided, I now have a basic understanding of ladder logic, and RSLogic 500. The program is for a robotic gasketing machine and this is the ladder logic controls the gasketing machine and allows the robot (controlled by adept cpu). Tbe reason that I was asking about that one piece is that it is the first line of the program and I understood how to write the I:7.0/13 but not what IB16 was and I did'nt know how to write B16 (U) 16 but your example of it helped greatly. Thank you Ryan

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