Troubleshooting SL 5/05 1747-L551 Ethernet Comms

[renzoduran 0]

Hello, During normal maintenance the PLC was shutdown and power removed. Once the maintenance job was done the PLC will not power up and load the programm. The PLC was working fine the day before. The fault led flashes with the enet led flasing also, after a few seconds the enet let turns off and the fault led remains on (not flashing anymore), all other leds turned off. Tried to establish communications via the ethernet but the rslinkx does not finds the PLC on the network, changed the power supply with a new one, no effect. Changed battery, no effect. Tried with the RS232 with no results either. Thanks in advance. Regards, Renzo.

[Armadillo852 25]

According to this bulletin from Allen Bradley: 60708 - Certain SLC 5/04 ser. C and 5/05 ser. B or C processors may hard fault with solid red FAULT LED It is a problem with the SRAM. They also say it will typically occur after a power cycle. Per AB: Resolution: Customers should return affected modules to a Rockwell Automation repair facility for replacement of SRAM by contacting Rockwell Automation Technical Support at (440) 646-3223, after confirming that their controllers are exhibiting the functional issue described. Tech Support will provide troubleshooting assistance and if they confirm this product issue is present, they will document it in the case notes. Once Tech Support has confirmed the issue is present, the customer may contact their local Allen-Bradley distributor and request replacements. Allen-Bradley Distributors should take the following actions: I hope it is ok to quote AB here. If not, please let me know. I don't want any trouble.

[renzoduran 0]

Hey Armadillo852, Thanks for the post. I will check the the revision of the processor. By any chance do youy have the AB document or know where I can download it? Thanks again. Regards, Renzo Edited 14 Jul 2010 by renzoduran

[Armadillo852 25]

If you go to: http://www.rockwellautomation.com/knowledgebase/ then just type in 60708 in the search bar and it will be the first one.

[renzoduran 0]

Armadillo852, This is the picture of the PLC processor. Does this tells you something? I think this might be my problem. Thanks for the tip. Regards, Renzo.

[Armadillo852 25]

Affected modules include 1747- L54X and 1747-L55X modules with date codes between 0504 and 0805 (May 2004 to August 2005). I do not think this one qualifies, however, it still sounds like the problem. I would call AB and see what happens.

[renzoduran 0]

Thanks Armadillo852.

[OkiePC 14]

This is a really wild WAG, but we recently had something similar. A tech shut down a spiral freezer controlled by a 5/02. It was running, he just needed to check something mechanical inside. He fired it back up and nothing. No LEDs on the CPU, and no power LED on the power supply. He replaced the power supply, and it did not help. Then he noticed the voltage jumper on the power supply (both original and new one) was set for 240V and our machine uses 120VAC. He switched it to 120V and everything was fine. I checked the voltage going to the power supply and found about 128vac. Somehow, the machine had enough voltage to function even with the power supply jumper set wrong. Later, we found out the power supply had died during the sanitation process the previous night, and had been replaced by one of our guys who's more of a mechanic than an electrician. At night, our plant voltage goes up quite a bit for a number of reasons, so that must be why it fired up and stayed running until the next day. This is the only time I have ever seen that happen, and I wouldn't have believed it if I hadn't seen it. I know the power supplies ship with the voltage jumper set to the higher voltage, because they won't blow up with half the required voltage, but they will if they are fed double voltage. I have installed several of them over the years forgetting to move the jumper, but never had one light up (they will sometimes blink for a second) when supplied with 120v and set for 240v, but like they say, for every rule, there's always an exception. Just something to think about.

[PackerFan 0]

Renzo, Did you ever get resolution to this? I too have a 5/05 L552 processor with this issue (which is different that all the replies you received here). The processor boots with the FLT blinking and the ENET blinking (2 slow blinks, then 4 slow blinks, then 9 or so quick blicks ...2 slow blinks, then 4 slow blinks, then 6 or so quick blinks) once this sequence is done then the FLT goes solid red with no other lights. The mfg date is in 2002 like your picture showed yours was and so doesn't directly apply to the issue the other posters mentioned. The symptoms of my processer were the ENET port locking up occasionally at first but then more and more frequently until recently it would not communicate and hard faulted. Defaulting the processor does nothing and I've tried moving the protect jumper for a firmware upgrade and found that the ENET light continues to blink in the same sequence, which I assume is some error code that I have not found a decoder for. Thanks, Matt

[renzoduran 0]

Hi Matt, We found that the problem was the on the comms modules. Since the processor and comms are located at the same board I had to buy a new processor. The damage was caused by the ethernet port. A current was induced on the wiring due to high voltage discharge (lightning). The symptoms are the same odd comms problems and finally goes hard fault. There is no way to reset or do anything else with that processor. Change it. Regards. Renzo.

[PackerFan 0]

Thanks for the quick reply. Matt