With enhancement in mind, consideration is being given to using a graphical HMI to perform the functions now being done with stand alone data logging equipment. (Agilent with 0-10V signals)
The need is for only a hand full of analog channels (8) to be displayed ( graphical and/or, digital display on the HMI)
Presently, all available slots of the 90/30 331 are filled, and there is not room to just replace the back plane with a ten slot unit.
I see two ways to accomplish the task.
(1) Add an expansion or remote panel located in the same cabinet, populating the new panel with the required analog input card(s). Adding logic into the present program. to read register data to the HMI.
or, as easily, add a complete (duplicate)PLC unit with it's own processor and the same five available card slots. reserving this second plc for all analog I/O, present and future. A separate logic program dedicated to these analog inputs and register locations.
The present setup has no analog I/O. As mentioned, these functions handled by the DA hardware displayed and recorded on multiple PC applications. The present I/O easily accommodates all system operation functions with spare channels available for future needs.
As these older GE plcs appear to be ubiquitous, cost either way does not seem to be an issue. The HMI allows multi plc serial by rs232, 485 or ethernet communication.
If there were a way to read the present analog signals directly into the HMI display, That would be the best of any option, but I have not seen that function offered ;-)
Considerations on schemes?
The need is for only a hand full of analog channels (8) to be displayed ( graphical and/or, digital display on the HMI)
Presently, all available slots of the 90/30 331 are filled, and there is not room to just replace the back plane with a ten slot unit.
I see two ways to accomplish the task.
(1) Add an expansion or remote panel located in the same cabinet, populating the new panel with the required analog input card(s). Adding logic into the present program. to read register data to the HMI.
or, as easily, add a complete (duplicate)PLC unit with it's own processor and the same five available card slots. reserving this second plc for all analog I/O, present and future. A separate logic program dedicated to these analog inputs and register locations.
The present setup has no analog I/O. As mentioned, these functions handled by the DA hardware displayed and recorded on multiple PC applications. The present I/O easily accommodates all system operation functions with spare channels available for future needs.
As these older GE plcs appear to be ubiquitous, cost either way does not seem to be an issue. The HMI allows multi plc serial by rs232, 485 or ethernet communication.
If there were a way to read the present analog signals directly into the HMI display, That would be the best of any option, but I have not seen that function offered ;-)
Considerations on schemes?
