ML 1400 Major Fault

Has anyone had similar issues to the one I'm experiencing at the moment?

We have had a process running successfully on a ML1400 for a number of months. RFID ASCII data coming in on both Channel 0 and 2 which is processed and stored in arrays. The data is accessed remotely (Ethernet) over company network using INGEAR drivers to SQL database.

About six weeks ago the Processor started to fault, indicating "internal Software Fault" The program was re-installed and ran again all day with no problem. A search found possibility of power spikes being a possible cause. With a number of VSD's in the vicinity this was quite possible.

To date I have installed Surge suppression on incoming power supply, data isolator-repeaters on RS232 transmission lines and isolated the I/O with opto relays. The receiving App indicates the fault happens around 12:30 in the night.

I have swapped out the ML1400 with a spare numerous times but both fault at the same time. I then had both of them in the office some 100 meters from the PLC cabinet. One had the process program running and I can see the remote app polling the PLC for data every second. The other processor had a test program running, both connected to a CISCO 2960 managed switch.

When I came in the next morning they had both faulted... this would lead me to belief that either the site server or the managed switch is causing the problem??

Is the fault you are experiencing the PLC failing to communicate to the SQL database, or is it the PLC that is faulting

If its the Comms to the SQL I wonder if they daily backup the server at 12:30am and stopping the messages being passes and hence then faulting.

If its the PLC faulting have you been online into the status file to find out what fault is logged

I live and work 40 to 50 km north of Invercargill and the early hours when our load is very low is the time that we have any of our fall overs on PLC'S and even then its always on the same two PLC's a PLC5 and a SLC 500, we tend to blame over voltages, to add to our problems our Hydro alternator is supplying most of our load at that time of the day.

I dont feel that you would suffer much with voltage problems in Invercargill.

The second processor only had a few lines of code unrelated to the processor which has faulted numerous times previously.

The common factors are both ML1400, connected to the same switch and power supply.

No longer based in Invers, now in Balclutha.

So with you being in Balclutha now that means you share the same 110 kv line as us between Invercargill to Dunedin or Roxborough which is near to overload until Transpower brings the 220 kv into Gore to split the line.

Now about 6 weeks ago the dairy farming load in our areas disapeared for the calving period along with 3 dairy factories and also the meat plants dropped the evening shifts and in some cases the day shift also
Now the night load after midnight is just about non existant so we suffer from overvoltage after midnight.

Should I also mention at your end of the line hydro genereration and a wind farm feed in also.

Now as for the error code you show I have nothing at home as a reference so maybe someone else can pick up on that.

Gil47 said:

Now as for the error code you show I have nothing at home as a reference so maybe someone else can pick up on that.

Click to expand...

Here is what the manual says. Pretty much says what you are pointing to
power issues.

industrial said:

A search found possibility of power spikes being a possible cause. With a number of VSD's in the vicinity this was quite possible.

Click to expand...

I have the sneaking suspicion that "power spikes" and "ground loops" are Allen-Bradley's way of saying "we have no idea why this happens, so we're going just going to say it's voodoo magic."

brstilson said:

I have the sneaking suspicion that "power spikes" and "ground loops" are Allen-Bradley's way of saying "we have no idea why this happens, so we're going just going to say it's voodoo magic."

Click to expand...

I thought voodoo was what made it work to begin with.

brstilson said:

I have the sneaking suspicion that "power spikes" and "ground loops" are Allen-Bradley's way of saying "we have no idea why this happens, so we're going just going to say it's voodoo magic."

Click to expand...

Based only upon how often this question comes up in this forum, it appears that AB currently offers some PLCs that fail in industrial power environments that don't tend to facilitate such failures with other brands and/or models of PLCs.

Mickey showed a page from a manual which jogged my memory

Do you have an earth wire connected to the Earth terminal on the PLC
If it is mounted on a DIN rail , is that DIN rail earthed

On all Allen Bradley PLC,s and probably all PLC,s the attachment of a good solid large Earth wire is important if you wish to avoid niusance troubles