Explain greater than instruction using example

Application:-Explain greater than instruction in the PLC. Write PLC program for explanation using ladder diagram language in the Programmable Logic Controller (PLC).

Components:-Programmable logic controller, HMI panel, wires, 24 VDC lamp, 24 VDC power source, 24VDC temperature controller.

Diagram:-

Explanation:-

Consider a simple temperature controller example for explanation of greater than (>) instruction in the Programmable Logic Controller (PLC). Here we have considered simple HMI (Human Machine Interface) for display and programmable Logic Controller (PLC) for programming. Consider one temperature control which is displaying the temperature given by temperature sensor, here we haven’t considered analog signal calculation and scaling so we directly consider actual value in the PLC. Here if the actual temp value in the actual temp box is greater than set temp, temperature indication will be ON.

If set temperature is 100 degree and temperature read by temperature controller is more than 100 degree or consider 102 degree, lamp should be ON because 102 degree is greater than 100 degree.

PLC program:-

Write the ladder program for above application using ladder diagram language. Here for ladder logic we can use any supported PLC system like S7-1200, S7-300, S7-1500 or any other PLC which can support this instruction. For PLC logic we need digital inputs and outputs.

For our application lamp is digital output. Set temp is the input word.

Digital Output:-

Temp Lamp=Q0.0

M Memory:-

Set temp.:-MW10

Actual temp:-MW20

PLC program Explanation:-

In network 1 actual temperature (MW10) will be compared with set temperature (MW20). So if the measured temperature (MW10) is greater than set temperature (MW20), temperature indication lamp (Q0.0) will be ON

In greater or equal (>) instruction, two operands are compared, we can set data type in comparator instruction.