Design a PLC program to control the liquid level in a tank. A level transmitter is used to measure the tank level into a standard current signal from 4 to 20mA as illustrated in the below process diagram.
Start/Stop PB latched with memory B3:0/0.
B3:0/0 enabled to turn on agitator (O: 0/0), Solenoid valve 1 (O:0/1) and Solenoid valve 2 (O:0/2).
Scaling block is used, Level transmitter gives output in mA (N7:0), to convert that into PLC range (N7:1), and scaling block is used.
Refer to the above tabular column for a respective range of values.
According to the program logic, we need to turn on the PUMP (O:0/3) at tank reaching 75%
And the pump still is in ON condition up to 25%, so comparator blocks are used to get this condition.
Agitator motor contact also connected in series as mentioned in program logic.
Memory coil connected to turn ON pump motor output.
High-level alarm should turn ON when tank reaching 90% and should not turn off until alarm reset (I:0/2) is pressed.
Greater than or equal block is used to compare the real scaling value(N7:1) and register value.
Low-level alarm should turn ON when tank reaching 10% and should not turn off until alarm reset (I:0/2) is pressed.
Less than or equal block is used to compare the real scaling value(N7:1) and register value.
We can use this example to understand the programming logic in Allen Bradley Programmable Logic Controller (PLC).
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sir i having level sensor problems in delta AS228R how can i solved this problem plz reply me
Ya you can solve it