$7-$X$4$

In a blending facility $($see Figure $7-$X$1),$ tanks T$-1,$ T$-2,$ and T$-3$ charge to blend tank T$-4$ through a mass flowmeter $($FT$-$T$4,$ with totalizer FTOT$-$T$4).$ The equipment in the figure are the batch charge equipment module for this mixing unit. The batch charge equipment module has phases T$1$Charge $($MassTarget$),$ T$2$Charge$($MassTarget$),$ and T$3$Charge$($MassTarget$).$

a$)$ Write the phase T$2$Charge$($MassTarget$)$ which charges MassTarget kg of the contents of $T-2$ to T$-4.$ The phase should start the tank circulating first, start the charge, end the charge when the flow totalizer indicates completion, then blow the line back to T$-2.$ Use a Sequential Function Chart for your solution.

b$)$ Write a state table for all $11$ devices in the equipment module to better document the Equipment states necessary to run the T$2$Charge phase.

c$)$ Write Hold, Stop and Abort logic for your phase. Indicate a re$-$entry point for Restart after Hold.

Figure $7-x1$