Explain IN Range instruction or value within range instruction using example

Explain IN Range instruction or value within range instruction using example

Application:-Explain IN_RANGE instruction using an example . 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:-

We can use IN_RANGE (Value within range) instruction when the variable is within a specific range. You can specify the value range for the MIN and MAX inputs. The IN_RANGE instruction will compare the variable value with the values of MIN and MAX value and sends the result.

For an explanation, we can consider a simple example so we can understand easily. Assume one application in which we need to operate a green lamp if the actual temperature is between MIN and MAX value which can be set by HMI. And if the actual temperature is not between MIN and MX value, operate a red lamp as shown in the figure. Assume analog scaling of the temperature value, so as sown in figure measured value s 50 degrees and MIN limit is 45 degree and MAX degree is 55 degree. So for the above example temperature is within range and the green lamp should be ON.

PLC program:-

Write the ladder program for the 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 lamps are digital outputs. MAX and MIN values are input words.

Digital Output:-

Temp OK lamp=Q0.0

Temp not ok Lamp=Q0.1

M Memory:-

Actual temp. =MW2

MIN temp.:-MW10

MAX temp:-MW20

PLC program Explanation:-

In network 1, actual temperature is measured or stored in MW 2 and in MIN we can set minimum range of the temperature also in MAX we can specify the maximum applicable range of the temperature.

So here we have used IN_RANGE instruction which will compare a variable with MIN and MAX values and if the variable value is within range, green lamp (Q0.0) will be ON and if not then red lamp (Q0.1) will be ON as shown in network 2.