This year’s upgrade was much more involved than last year’s upgrade as it was in the main mixing and processing area of their process. The system comprised of a number of wet and dry ingredients precision dosed and blended in a common mixer then passed into a former area in a high speed operating process. The existing control system incorporated a number of Fischer and Porter instruments with a PLC 5 controller and a number of remote PLC racks. One of the largest components of this year’s upgrade was the replacement of the sites Conductor NT human machine interface with screens on the sites current Factory Talk View Studio (Plant PAx) system.
The Upgrade Included:
1. Conversion of the Existing PLC5 Code into the Logix5000 Format.
Our engineers used the Rockwell PLC 5 conversion tool and then worked through the project to check that the conversion was thorough and correct. This process meant that the migration of the project was smooth from an operation, structure and maintenance familiarity point of view. It also meant that the start-up after the shutdown was relatively seamless. It was decided not to use the available Rockwell conversion chassis and therefore close to 1000 I/O were re-terminated. CJO Electrical were contracted to complete the terminating of premade cables to the existing marshalling strips and other wiring requirements
2. Migrating Conductor NT Screens to Factory Talk View Studio
Part of the upgrade was to move plant status and operation data previously programmed in Conductor NT to the Rockwell Factory Talk system using PlantPAx. This involved the integration of the PlantPAx add-on instructions in the PLC code and a number of operational and trending screens added. The alarming and historian aspects of the package were also updated. The screens methodology was also changed to give the operators a more graphical interface including ‘situational awareness’ to comply with global standards in HMI programming. This allows operators to better recognise and deal with issues as they arise in the plant.
An overview screen uses the situational awareness type indication by displaying alarm boxes around the areas associated with an alarm. This directs the operator to click on that area which navigates them to the associated screen where the alarm will be displayed. These alarm boxes have four different severities based on their importance.
3. Integration of Redundant Instrumentation Control into the PLC.
A large amount of the plant control was previously carried out using standalone Fischer and Porter instruments. The Each instrument needed its FORTRAN code deciphered and converted to RSLogix5000. Crossmuller meticulously and thoroughly deciphered the Fortran code and then worked out the best way and represent this in the Logix environment. This meant close and detailed work with the site engineering team.
Many PID control loops were contained withing the Instrumentation for precision liquid and dry ingredient control. This code was reprogrammed using Contrologics PIDE instructions. The products were then tuned using Loop Tuner Pro software.
The change out was carried out in a very short shutdown period and the ramp to full production was immediate. Testimony to the thorough preparation and meticulous testing and startup strategy that was employed.
Crossmuller updated all electrical drawings and updated the site documentation. A detailed operating manual was also supplied.