Kings and Barnhams have a wealth of experience in the refurbishment of old and unreliable control systems whilst still using the existing plant. This project involved both our Automation and Electrical Contracting teams updating 3 control panels and rewiring all the existing plant on a grain storage site near Fakenham in Norfolk.
Our Automation team designed and manufactured a control panel that reused all existing conveyors, elevators, cleaners and fan motors as well as the existing bin slides, flap switches and bin level probe signals.
The Existing Installation was becoming unreliable this was replaced by the system below
The new control panel uses a 15” Human Machine Interface (HMI) touch screen and Programmable Logic Controller (PLC) to replace the existing plant mimic control panel which contained relays, push buttons and lamps. The HMI screen is able to offer the same graphical plant layout as on the old mimic so the new system will feel familiar to the operators. All push buttons and lamps are now incorporated into the HMI touchscreen software as well as Man/Off/Auto selectors for all drives.
Automatic running is only allowed if the selected routes bin slides, flap switches and bin level probes are in the correct state. If the feedback signals are positioned correctly then all plant will start automatically after a time delay in the correct sequence. If the plant was stopped or a fault was to occur the system will shut down all drives in sequence. As an extra safeguard against build-up of product ‘bung up’ sensors are fed back into the system controller. Manual running of any independent piece of the plant is especially useful for maintenance purposes.
The overall system is covered by an emergency stop arrangement complete with a fail-safe safety relay and system reset. The control system and software offers greater flexibility as additional routes and sequences can be added or changed easily at a later date by our software engineers.
The project also involved replacing and updating 2 more control panels and all the wiring for the 2 existing dryers.
Each control panel contained 2 soft starts for the 22KW fans, 3 direct on line starters for the burner motors and waste conveyor and an inverter drive for the discharge conveyor.
All push buttons and indicator lamps for control and monitoring of the dryer operation were door mounted into a mimic. The mimic also contained digital display units displaying fan running current and status, discharge inverter status and speed adjustment and dryer air temperature controllers.