We have an OEM machine builder who is supplying several machines that are networked together. They have proposed to move all relevant machine status information to one PLC and that PLC will be connected to Ignition.
Here is their question - **How do you want the data formatted? **
We are considering a data structure to poll a single tag structure for each of the machines and under that tag will have all of the data points that we are providing.
I’m not familiar with Allen Bradley data structures, we are a Siemens based facility and we have to turn off optimized block access because Ignition can access data block structures.
So, my understanding of what they want to do, is to transfer each machine status data structure to a master PLC and then make available those “Single Tag” data structures available to Ignition.
Can Ignition access (browse) this kind of tag?
Yes. Ignition has full visibility into Allen-Bradley Logix data structures, as long as the PLC programmer doesn’t deliberately set structure members’ external access to ‘None’.
However, if Ignition can connect to the individual machines, I don’t see any particular advantage to consolidating the data in one location. Ignition doesn’t have a limit on driver connections.
Thank you for your response so quickly. I’m am out of my element with AB PLC’s.
I am aware there is no practical limit on connections. But our Ignition subnet that these machine are connected to is getting crowded. I only wanted to provide one IP address for their group of machines.
Ah, so the ControlLogix will have two network interfaces. The Ignition Logix driver can route through a ControlLogix backplane to talk to an inner subnet, including legacy network technology, but concentrating the data at the boundary isn't a terrible plan. For me, I would prefer avoiding the engineering effort to maintain the data and data types in two PLCs, both now and in the future.
The 2 separately configured network interfaces is correct.
I know this is delving into systems integration design and I referred to several machines (it is 5 separate PLC’s in 5 box machines). For our network consideration I wanted to treat all the down stream machines as remote I/O and they can be on their own subnet.
Thank you for your input.