Ladder
Diagram
when
transmitter
is
calibrated
Program Description
RUNG001 comprises all the conversion needed to control level of the tank.
Output of transmitter is in current signals which is 4-20mA.
When output is 4mA, Analog Input Module converts it into 16bit equivalent hex numbers. Hence
when input to Analog module is 4mA, it stores 0000h into register and when 20mA, it stores FFFFh into
register. Here register N7:0.
Temperature range of RTD PT100 is -200°C-650°C. By converting it into equivalent hex, change in
value per centimeter is 77.
Value of N7:1 is then multiplied with the preset value of liquid temperature. That is here 300°C.
This multiplication is stored into N7:2 register. This gives data which is again multiplied by 6 and
stored in register N7:3 which gives full output when preset is reached. Digital to Analog conversion of
value stored in N7:3 is performed inside the processor and equivalent mA current is received from
terminal O:4.
Current to Pneumatic converter then converts current signals into equivalent 3-15psi pneumatic
signal and adjusts valve opening.
In other method, when transmitter is calibrated, transmitter is tested in the laboratory and calibrated
such that at 0°C, it gives output 4mA and at 100°C it gives 20mA.
This 4-20mA can be directly converted into hex from 0000h to FFFFh. Then programming would be
to just move this converted data into output which again converts 0000h-FFFFh into 4-20mA equivalent
to actuate control valve.
http://www.sanfoundry.com/plc-program-heat-liquid-tank-steam-flow/
PLC Program to Sort Parts for Quality Control on Conveyor
This is a PLC Program to Sort Parts for Quality Control on Conveyor.
Problem Description
Parts are moving on the conveyor from one process line to other with a constant speed. Out of 1000 part,
one part is taken out for quality check. Implement automation of this
process in PLC using Ladder
Diagram programming language.
Problem Diagram
Problem Solution
To detect the parts, detector such as proximity switch, optical sensors or any other sensor is used.
Connect output of this detector to Input Module of PLC which sets and resets image memory according to
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