Ajay Garg

Hi All. We have the Micrologix-1400 1766-L32BWA PLC, and we are in process of understanding how to read data from it using our custom, simple, external application in a high-level language (C in our case). Following is what we have achieved so far : Been able to connect the PLC with a laptop, and able to browse (via the PLC's embedded web-server) over PLC's-IP 192.168.1.102. The PLC is pre-programmed, and have the (default) program-files and data-files (picture PLC-files.png attached). Also, some data is shown (eg. N7-Data-File.png attached). Also, we have following strict limitations : Nothing is to be changed inside the PLC, so any (ladder-logic) programming inside the PLC is out of the question. The only external interface available to us is the Ethernet (physical) interface. None of RS232, RS485 is available to us. Now, for simplicity, let's say we want to read just the values in N7 data file (using our custom, simple, external application in a high-level language). Since 1766-L32BWA is a A-series PLC, so I guess Modbus-TCP is out of the question. So, what would be the best way to read data from N7 data file via Ethernet (physical) interface. Ideally, we would want that our external application fires a command, and receives the appropriate response from the PLC. We have been reading that Ethernet/IP could be an option, but have been unable to find any concrete Request/Response example (of Ethernet/IP packet).    I am sorry if I sound too noob. Hoping to get some help from the experts ...   Thanks and Regards, Ajay