Equipment Type PLC
Industry Sector Manufacturing
PC or Computer based No
System Age Unknown
CNC Milling Machine.
The system is used to manufacture aircraft parts and is
controlled by PLCs.
Description of the Problem
- At the 31/12/1999-1/1/2000 transition, the PLC's BIOS
resets from 31/12/99 to 4/1/1980;
- NC program data with the current date (1/1/2000) is then
downloaded from the DNC
- There will now be a date conflict between the downloaded
NC data and the internal date.
How was it Identified
Information from supplier states that current 'x' series
PLC and operating system software
are BOTH non-compliant.
Analysis and rollover testing confirmed the non-compliance
of these PLC and this version of
the operating software.
What was the Solution
Upgrade of operating system in 3 stages.
Consequences for the SYSTEM Erroneous Result
Consequences of failure to the BUSINESS
Confusion over NC files which are downloaded over the site
network due to date
There are three of these machines dedicated to the same
task, all are identical and
therefore consequence of failure is increased threefold. As
far as known, these are the only
machines available to manufacture the above aircraft parts
to the proven method at this site.
For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
This archive was generated by hypermail 2.1.2 : Tue Jun 05 2001 - 22:52:15 EEST