The Event Action block can control a digital output based upon an analog value received from an upstream block. For example, suppose your process requires that a 100-gallon floating roof tank to be 80% full at all times. Using an Analog Input block, you can measure the level of the tank and pass this value to the Event Action block. The Event Action block then tests the analog value to determine if it should:
- Open or close the digital valve controlling the liquid flow.
- Run a program that opens an emergency drain and sequentially shuts down the pumps.
The following figure shows how you can use an Event Action block to control digital points.
