Ladder Diagram to control level of two tanks Program Description
RUNG000 is a master start/stop rung to Start and Stop the entire process.
RUNG001 is for controlling Connecting Valve output O:2/1. It is opened when LHS1 I:1/0, Pro1 Done I:1/5
and LLS2 I:1/3 are detected. And it is closed when LLS1 I:1/1 is detected, or in other words, when Process 1
Tank is empty.
Important thing to note here is that if Tanks’ size/shape were not same and any one XIC contact from O:2/1,
I:1/0 or I:1/5 was not connected, there would have been a chance of malfunctioning/overflowing.
RUNG002 is for controlling Inlet valve O:2/0. It is allows the inlet flow by opening Inlet Valve whenever Low
Level switch of Process1 Tank LLS1 with address I:1/0 is detected.
RUNG003 is for controlling Outlet Valve with address O:2/2. It allows the process material to flow out when
Pro1 Done I:1/6 is detected.
Consider any set point of Process1 and Process2 as I:1/5 and I:1/6.
Runtime Test Cases Inputs Outputs Physical Elements
I:1/0 = 1, I:1/1 = 0
O:2/2 = 1
Open Outlet Valve
I:1/0 = 0, I:1/1 = 1
O:2/0 = 1
Open Inlet Valve
I:1/0 = 1, I:1/5 = 1, I:1/3 = 1
O:2/1 = 1
Open Connecting Valve
I:1/0 = 0, I:1/1 = 0
O:2/0 = 1
Open Inlet Valve
I:1/0 = 1 O:2/0 = 0
Close Inlet Valve
I:1/1 = 1 O:2/1 = 0
Close Connecting Valve
I:1/3 = 1
O:2/2 = 0
Close Outlet Valve
PLC Program to Control Level of a Single Tank
This is a PLC Program to Control Level of a Single Tank.
