I currently have an AB7554 gateway. I need to extract some data from a CompactLogix L43 PLC and then post it to a local broker via the MQTT protocol. In the documentation, it says that I can select the number of input and output bytes that I want. By default, 20 input and 20 output are configured. What I don’t understand is how can I extract a particular tag from the PLC database? it also says that I don’t need to do any kind of programming on the PLC side. So how can I extract that tag that I require and not another? Thank you for your attention.
I think the “No Programming required” statement is a little misleading in this case. You don’t need to write any ladder logic, message instructions or other code to add the device to the PLC. You add it as either a generic IO device, with assemblies 100 & 150, or add it with the EDS file. Both options add it as IO on you PLC for you to setup to read or write data. It does not have an option to read a particular tag and then that directly to an MQTT broker.
Once you have the PLC side configured you can configure the MQTT side using the web interface and ACM IIOT. This is explained in section 4.3 of the user manual. hms-scm-1202-109.pdf (hms-networks.com)