LED signs in automated weigh stations are normally controlled by a PLC or a small controller. Using complex digital controls capable of advanced calculations for a simple on/off sign is costly and inefficient. Programming takes hours or even days to complete and program maintenance consumes additional time and money.

System Requirements
Weigh station I/O modules need to have local intelligence to perform on/off controls for the signs. Moreover, settings for the I/O module need to be simple and easy. The remote server also needs to be notified to track each time the switch is turned on or off. Since the weigh stations are separated across many different locations and polling over a large network is almost impossible, active on/off status updates are essential.

System Description
Each weigh station has an on-site control room equipped with a simplified control box. Operators simply use the switches to turn the arrow and direction signs on or off. Moxa's ioLogik E2212 is equipped with an intuitive IF and THEN Click&Go logic. It takes just five steps of mouse clicking to finish the settings.

The system also has a remote server that keeps both sign operation and weight records. The ioLogik E2212 can actively send out sign change status without using traditional polling methods. This type of active messaging eliminates the concerns associated with polling over large networks.

In addition, the scale itself has a serial port for transmitting weight records. Uploading these records to a remote server requires a serial-to-Ethernet device server. In the past, device servers at automated weigh stations often encountered system hanging problems as incoming serial data would flood the memory. However, Moxa's NPort 5450 serial device server addresses this problem by flushing its memory to prevent such overflow.

Benefits

• IF-THEN control logic makes configuration as easy as 1, 2, 3
• No programming needed, reducing time and costs
• Report by exception for real-time I/O status update
• No polling required
• Rugged serial-to-Ethernet solution with 5-year warranty

Project Implementation
ioLogik E2212: Active Ethernet I/O with 8 digital inputs, 8 digital outputs, and 4 configurable DIO

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