Write constraints for the following examples in the form:

IF $[$Logical Expression$]$ THEN $[$Action$($s$)]$ AFTER $[$Delay$]$

Define alarm levels as necessary. Use interlocks where you can.

P$-3$ pumps out T$-2.$ If the continuous level LT$-$T or if level switch LSLL$-$T$2$ is true

than do not allow P$-3$ to continue pumping.

The pressure in R$-2$ is measured with PT$-$R$2.$ If the pressure exceeds the vessel

pressure rating of $100$ psig $($define a HighHigh alarm$),$ open the emergency vent valve

SV$-$R$2$V$.$ SV$-$R$2$V is a fail open valve.

If the temperature in R$-5($measured redundantly TT$-$R$5$A and TT$-$R$5$B$)$ exceeds $140C,$

stop charging reactants to the reactor $($block valves SV$-$R$5$E and SV$-$R$5$C$)$ to prevent a

runaway reaction.

$T-72$ is emptied using $P-72$ through the flowmeter FT$-$P$72.$ When the tank is empty of

liquid, the flow will fall below a minimum $(100k\frac{g}{m}in).$ Shut off the pump when the flow

indicates an empty tank. Use a delay to avoid early shutdown. Why is a delay on this

constraint essential, and not just a good idea? Note: The digital command signal to start

P$-72$ would be called MS$-$P$72$