CHMI & xA
What is the exact difference between xA & CHMI?
why is CHMI cheaper when compared to xA? Even in CHMI systems, xA is installed. Then where comes the cost reduction?
Voted best answer
The major difference between the two offerings is the AC800M controller engineering. In Compact HMI, the "mirroring" between the programming tool and the HMI is turned off.
In 800xA, when you create a controller object ( like say an IO signal ) in CBM you automatically also get all of the Objects and aspects created in the HMI. If you create an object in the HMI (eg a Control Module or an Application Program), you also get the same object created in the Controller. So programming the HMI and Controller is fairly seamless.
In Compact HMI, you get none of that. When you create an object in the controller, you have to also manually create a matching object in the HMI. Because of this, Compact HMI relies on "PLC Connect" to make the link between the AC800M and the HMI. There is a lot more engineering work required to get the same functionality.
Everything else is really just "window dressing". The products are basically the same. Some or most packages that are designed for use in 800xA should also work in Compact HMI but may not be offered as supported features.