First step is to Download the Library Files
Step 1: Paste These Three Files GS.IDX, GSB.LIB and Gscode.HEX in to Library Folder
if you are using Proteus 8 then Library folder will be within the data Folder (Proteus 8 Professional\Data\LIBRARY )
Step 2: Now Open Proteus Software and Search for Gas Sensor ( You Can Get All Gas Sensor,s Library From MQ-2 to MQ-9 )
Step 3: Open Arduino Software and Click on File and Then Preference and Tick Both of the Option "Compilation and Upload " After Writing Your Code, Click on Compile Then You Will Get the Link of Your Hex File at the Output Go to That Place and Get Your Hex File.
Step 4: How to Add Hex File in to Arduino So It,s Easy Double Click on Arduino and Then Click on Program File and Add Your Hex File .
Step 5: Now It,s Time to Test and Simulate the Gas Sensor in Proteus Software
, first of all double click on Gas sensor and add the Hex file ( Hex file you already download -- GSCODE.HEX) now when you turn test pin logic in to "1" it,s mean there is a gas in atmosphere by doing this the OUT pin logic will goes HIGH