PLC-Link (PLC to PLC)

I have been a long time that I would like to post this post.

PLC-Link is a Delta protocol to share easily memory area between 2 PLC’s.
Basically, the big advantage of PLC-Link is to work with Delta PLC’s as Remote I/O units.

Furthermore, you can use Delta PLC as Remote I/O or any other Delta device (Servodrive, Inverter, etc..) because the protocol used to share the info is Modbus.
Today we’ll focus on how to communicate one PLC master with 2 PLC slaves.

Network Structure:

Hardware:
The communication will be Modbus RS485, so the wiring is so simple, two twisted pairs from connector to connector.

Protocol:
We decide to use 9600, 7, E, 1, ASCII, but you can use higher baudrate. In fact the new S2 PLC series (SS2, SX2, SA2, ES2 and EX2) can reach 921Kbps!!

Memory Mapping:
The plan is to share 6 registers from the slave 1 and put it inside the memory of the master.
And on the other way around too, put 6 registers of the master on the memory of the Slave one.

See below table

As you could see on the Slave software we transform the first three shared words to Slave Inputs and Outputs.
This is the proper way to read remotely the I/O of the slave into the master.

Programs:

PLCLink

Remember to enable PLC-link on network 5 to start to share.
And if some trouble occurs just try to reset the communication with the RESET_Com Symbol.

Enjoy