Sand Plant Automation

Process

In a ferrous foundry, Sand Plant requires accurate batching of raw material such as return sand, fresh sand, bentonite, coal dust, water etc. to produce high quality moulds. Also, all the electrical / pneumatic equipments in the plant are required to be operated in a sequential manner as per the plant design.

Solution

This system comprises of an Operator Desk/Panel, Integrated Motor Control Centre, PLC (Programmable Logic Controller) with serial interface to a PC, Weight Indicators, Load Cells, Level Sensors, RTD, Zero Speed Switches, Pull Chord Switches and Limit Switches.

The PLC system comprising of various interface cards is interfaced to the various sensors and signal-conditioning units. The load cells are connected to the weight indicators, which in turn are interfaced to the PLC. The RTD is used to measure the sand temperature and is connected to a signal-conditioning unit which gives an analog signal to the PLC.

Other sensors such as Level Sensors (for monitoring the level of materials in various storage bins / hoppers), Zero Speed Switches, Pull Chord switches (connected to the belt conveyors) etc. are also connected to the PLC.

The PLC system operates all the electrical equipments through the MCC panel and also the pneumatic ploughs based on the sequential process pattern programmed. The PLC also monitors the trip status of the devices and indicates the same on the operator desk/panel MIMIC. The Operator desk houses the PLC system, push buttons and switches for operating the various output devices, weight indicators, and indication lamps.

The Computer is used to log the process parameters for the Plant and is connected to the PLC by a serial link. The computer also generates customized reports automatically, which can be taken on a Printer.

PLC Based Sand Plant Automation