PLC Developers Guide /
Network Architecture
Each ConveyLinx Module communicates to its adjacent modules and to any connected PC or PLC via Ethernet physical media. All ConveyLinx Modules recognize (4) TCP/IP based protocols:
- Modbus TCP
- Profinet I/O
- Ethernet I/P
- CC-Link IEF Basic
Modbus TCP is the “native” protocol for communications between ConveyLinx Module and the EasyRoll / EasyRoll+ PC software. When ConveyLinx Module are used even for basic ZPA control with no external connections to a PC or PLC, they utilize Modbus TCP for inter-module communication.
Each ConveyLinx Module internal data structure is arranged and addressed as Modbus Holding Registers. The on-board communication and control processes attach logical meanings to each holding register and read and write data to specific registers to initiate and/or react to events. Certain registers contain information as to how the ConveyLinx Module is configured (MDR type, speed, direction, etc.) for its local controls. Other registers are used for inter-module communications for conveyor operation. For example, when an upstream ConveyLinx Module has a Carton ready to discharge to its neighboring downstream ConveyLinx Module, the upstream ConveyLinx Module will write a specific value to a specific address in the downstream ConveyLinx Module’s internal registers. The downstream ConveyLinx Module’s on board logic monitors these registers and knows that a specific value means that an upstream Carton is coming and to engage the proper control logic to convey the Carton.
Because ConveyLinx utilizes an open architecture (Modbus TCP) for inter-module communications; with proper definition and expected usage of certain register address locations, external control devices (PC’s and PLC’s) can easily interact with ConveyLinx Module to monitor and control various points along the conveyor path.