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The computer is not communicating with the processor. Please verify that you are using the correct cable (1747-CP3) and the cable is securely plugged into the RS-232 port of your computer and the RS-232 port of the SLC-500 processor and the communication driver is correct.
Hi, we've worked to figure out the CIP protocol for a few days. We intended to write a 2 way communication program using socket between Linux and PLC. However, the AB programming manuals didn't specify all the data that is sent. And the only example of real data (by each byte) is from a PLC to another PLC.
We tried to send a packet of bytes (from the example) to the PLC but no response from the other end.Maybe it's easier to implement only 1 way communication. So is it possible to set the PLC program in RSLogix 5000 and gets it to send the tag values we need to a local IP address (PC) and we'll decode it?
How does MSG instruction work in this situation? Or are we even on the right track to tackle this problem? Are you trying to read a specific Tag inside the controller, or establish a cyclic I/O connection?There are a handful of Linux projects for connecting to ControlLogix; are you using one of them, or starting from scratch?Yes we are trying to read some tag values in the controller, mostly are temperature readings from thermocouple and the valves positions. It's better if we can start from scratch because we only need limited functions, and keep the program size as small as possible to run it on a Linux single board computer. But I'd like to see some linux projects and I'm sure it will be helpful to us. I was able to exchange data between a CompactLogix and my linux box using the CIP/EthernetIP specs, the logix5000 data access manual and Wireshark.That should be all that you need.Hi there, instead of Wireshark, we used another TCP/IP sniffer to track the packets sent and received.
But still we encountered two problems.1. The CIP/EthernetIP spec sheet didn't tell us the meaning of all bits that are sent to the PLC. Some definitions are very vague.2. When we used an old version of CELL that was mentioned above, it can talk to PLC. But the process of exchanging information, or to shake hands with PLC, is different from what we read in the spec document. Although we can't successfully retrieve any tag value by using this program, the sniffer showed that it did communicate successfully with PLC. In case you don't want to re-invent the wheel, there is a popular automation software package called Ignition (that features cross-platform support (Java) and is based on integration with SQL databases.I'm running it on an Ubuntu 10.04 server (a tiny little FitPC2) with MySQL.
Even without the visualization package it's a tidy and relatively inexpensive transaction manager for Logix-family controllers and SQL. One of my customers for it, by coincidence, is in Edmonton.
In case you don't want to re-invent the wheel, there is a popular automation software package called Ignition (that features cross-platform support (Java) and is based on integration with SQL databases.I'm running it on an Ubuntu 10.04 server (a tiny little FitPC2) with MySQL. Even without the visualization package it's a tidy and relatively inexpensive transaction manager for Logix-family controllers and SQL. One of my customers for it, by coincidence, is in Edmonton.Thanks, Ken! I'll check it out.
How to set up Communication between an Allen Bradley PLC and LabView, through Ethernet/IP OverviewIndustrial Ethernet protocols are basic tools for compatibility and network communication. They add characteristics for reliability with standard Ethernet/IP to communicate over single or interconnected networks (Internet). LabVIEW uses the Ethernet/IP driver to interact with objects in the CIP object module on a PLC. The list of controllers that support this protocol can be verified on the manufacturer’s website. Step one: define the master device, aka the scanner, and the slave device, aka the adapter. The Scanner Class, the “Master”, will initiate both implicit and explicit communication and commands.
The Adapter Class, the “Slave”, only sends data if the data is requested by a scanner (master). The adapter (slave) device does, however, support explicit and implicit messaging. The Messaging class is used for on-demand data transfer applications or setup; this unit initiates data transfers by either device.To ensure that the LabVIEW driver for Ethernet/IP can communicate with your device, make sure that the device can act as a scanner (master). DO Supply Inc.
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