PLC 5 to CompactLogix Upgrade

Southern Flow was contracted by Forsyth County to upgrade the aging Allen-Bradley PLC-5 and SLC 5/05 PLC hardware to the current Allen-Bradley CompactLogix platform. The work consisted of four (4) PLC upgrades, two of which contained PLC-5 hardware and two that contained SLC 5/05 hardware. There were also four (4) remote IO panels for each of the four gravity filters that
contained PLC-5 remote IO. Southern Flow proposed a cost saving and innovative solution by utilizing the upgrade
hardware provided by Allen-Bradley that is intended to replace the PLC-5 with ControlLogix, a costly PLC platform and instead performed custom engineering to modify the Allen-Bradley upgrade hardware to be compatible with CompactLogix. This
provided the same performance increases and platform stability that the County was looking for at a much reduced price.

Our engineers spent many hours testing the PLC wiring configurations and communication with the modified HMI application in our office to ensure that the custom design was operating as intended and that start-up time would be minimal. All PLCs were connected as they would be in the field with fiber, and copper patch cables to ensure that communication paths were completely tested. Each point in the HMI was tested for proper mapping to each PLC tag. Once the factory testing was complete SFI coordinated start-up dates with Forsyth County.

Start-up was done in phases so as to reduce down time on the plant. The SLC plcs required a complete re-wiring of the IO from PLC to terminal block and was able to be completed and implemented in roughly one day. The PLC-5 plcs utilized the upgrade platform from Allen-Bradley and was able to maintain the existing wiring arms and panel wiring. The chemical PLC was able to be upgraded in roughly half a day by one technician causing minimal down time. The critical start-up was at the filter basins where there were four remote IO panels and one PLC that required upgrade from PLC-5 hardware to CompactLogix with only hours of downtime allowed. To accomplish this, Southern Flow provided a team of engineers and field technicians to simultaneously perform the hardware and software upgrades to the panels at one time. Our team started the transition at 8am and was able to have the plant filtering water again by noon the same day!

The Antioch WTP now has current PLC hardware in all control panels and will be functional for years to come.