According to the costs it was determined to establish a system controlled by a programmable logic controller (PLC) since these tools have been particularly designed for sequence control of production line and are consequently if possible matched to this application.
Maidstone mill compresses around 360 tons of cane an hour on 2 tandems: one diffuser which compresses 200 tons an hour and one tandem of milling which compresses 160 tons an hour. The cane yard layout at Maidstone with all the traffic control system components. The system contains of:
1. A PLC (programmable logic controller) which is placed in the weighbridge. This is the center of the system. The programmable logic controller is programmed in logic of relay ladder. The exacting PLC selected for this system can obtain 1194 program statements and has 12output and 16 input channels.
2. A lights set at the weighbridge which specifies to the drivers of hilo which haulier is to shift onto the weighbridge.
3. A lights second set, placed at the staging area of hilo, which shows to the drivers of hilo which haulier should move ahead into his queue of weighbridge.
4. A station of pushbutton to let direct vehicles of delivery, including all vehicles, which need to be weighed, to transmit a signal to the PLC to ask for a turn on the weighbridge.
5. A light set on the way out from the weighbridge gross which specifies to the driver whether to discontinue or go and to which tandem of milling it should go.
6. A panel of control in the weighbridge, worked by the clerk of weighbridge, which has the below features:
• Lights displaying which call light are on.
• Lights displaying which tandem are calling.
Channel of Input
• Lights representing if one tandem was ended.
• The switch of auto/manual.
• The buttons of reset and start.
• The buttons of stop and go.
• The switch of day/night sequence.
• The switches to activate the lights of call in manual mode.
7. A photocell on the tandem of milling queue lane to specify to the PLC when a hilo is requisite by the mill. Just a hilo is queued at the mill at any time.
8. A photocell on the queue of diffuser lane to specify the PLC when a hilo is requisite by the diffuser. At the diffuser, 2 hilos are queued. The PLC is correlating with the variety of system components.