Feature PLCs & Industrial PCs Rapid response saves the day
A West Midlands dairy has saved a potential £3,000 per hour in down-time when Mitsubishi Electric’s service engineers were able to diagnose a blender problem in double quick time and restore operation
expert advice and on the ground repairs. Mitsubishi can also offer ser- vice support for other vendors’ automation equipment.
The Mitsubishi technical support line took the call, evaluated the prob- lem and contacted Mitsubishi Electric’s Service Agent, NISCAM. Service engineer Carl Chadwick received the call, contacted the cus- tomer and took as much detail as pos- sible, then set off on the 33 mile journey to the plant, knowing that time was of the essence.
T
here are a number of price pres- sures impacting on the dairy industry. As a result, unsched- uled down-time can have severe consequences. Against this, there is the ongoing drive to boost productiv- ity by making upgrades to processes and machinery over the lifetime of the equipment, including modifications to PLC programs. In the vast majority of cases, such upgrades go without a hitch but when something goes wrong, it’s important to have an automation supplier that can be relied upon. A case in point occurred at a West Midlands dairy when it was noted that the blending plant was exhibiting some unexplained operation of the valves and showing various valve position feedback alarms.
Down-time from any operational failure is never good news and a return to full production was critical. Monitoring the system controlling the process didn’t reveal anything obvi- ously wrong but the site engineers knew they had to get the problem resolved as soon as possible and put in a call to the Mitsubishi technical sup- port hotline.
Assistance round the clock Via its System Service Group, Mitsubishi Electric provides added value services including 24 hour tele- phone support and a full complement of authorised engineers to provide everything from routine service to emergency down-time mitigation. The System Service offering supports both current and past generation product lines, with authorised service agents providing local engineers at regional centres and key partners providing
Automation SEPTEMBER 2013
Above: Mitsubishi Electric has a commitment to service and technical support, via its System Service Group, providing added value services including 24 hour telephone support
Right: with down-time
potentially costing the dairy £3,000 per day, the importance of effective program management can clearly be seen
It is not uncommon to find examples of Mitsubishi PLCs still in continuous operation after 20 or more years of ser- vice. So, finding nothing wrong with the PLC itself, Chadwick singled out one of the troublesome valves and started a code trace of the valve control logic.
the one loaded in the PLC, Chadwick quickly identified differences sur- rounding the valve control logic. It then emerged that modifications had been made by one of the dairy’s site engineers the previous Friday as part of ongoing efforts to improve produc- tivity. Chadwick’s suspicion was that the valve control modification had been implemented but with a very slight error.
Chadwick noted the changes then re-loaded the program and, after test- ing, found that the valves were now operating correctly, with no positional errors shown. Chadwick stayed on-site for a further 30 minutes whilst the process was started, to ensure all valves operated and the process sequence was stable. Finally, he saved the program as the latest version, and retained a copy for the Mitsubishi archive system.
Summary
This cautionary tale of course high- lights the importance of effective pro-
Locating the problem
It was found that there was a request to open the valve but no output to the open solenoid. The logic was checked against an earlier back-up taken three months earlier during a routine health check as part of the customer’s ‘Mitsubishi 3 Diamond Service Contract’ and key differences were found.
The site laptop was checked and found to have two versions of the pro- gram saved. One was fully com- mented, looking very much like the original post-commissioning work, and a second, later version.
Comparing these two programs with
gram management, fully commented documentation and regular back-ups as part of a customised Diamond Service Contract. The problem would have been difficult and time consum- ing to diagnose but for the fact that Chadwick already had an archived back-up against which to compare the incorrect program running in the PLC. With down-time costing the dairy an estimated £3,000 per hour, Mitsubishi’s local engineering support certainly helped to save the day.
Mitsubishi Electric
http://automation.mitsubishielectric.co.uk T: 01707 276 100
Enter 212 29
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52