What happens when RSLogix Emulate runs

RSLogix Emulate uses your computer's CPU to scan the rungs in your ladder program. The rungs in your program read inputs from and write outputs to the data table stored offline with your ladder logic project. The offline data table is also active during emulation.

RSLogix Emulate reads the ladder program and data table into your computer's memory before executing the ladder logic. The files on your disk are not affected by the emulator.

The basic order of events during emulation is no different from when a processor runs a project. The software scans your rungs, pauses to update the output and input image tables, and scans your rungs again. (During normal operation, the software repeats the program scan until you tell it to stop. There are other scanning modes you can use.)

Since there is no real I/O, the emulated ladder logic takes cues only from the state of the data table. To generate responses in your ladder program, you will need to change the value of the desired I/O bits, storage bits, or storage words acting as inputs to your ladder program.

Note Remember that the data table is always active, no matter which rungs are actually being scanned. It is not unusual to see inputs and outputs highlighting and values changing (like in an ADD instruction) on rungs that are not being scanned. If a dormant rung contains addresses that are being changed by an actively scanned rung elsewhere in the program , you will see the changing values on the dormant rungs.

What happens when you are "online" with the emulated program

When you are using RSLogix 5, RSLogix 500, WINtelligent LOGIC 5, PLC-500 A.I. Series, or PLC-5 A.I. Series online with RSLogix Emulate, the software owns the edit resource for the project. This means that you cannot edit the ladder logic that is in the software's memory. To change the project, you must edit the project offline and reload the project into RSLogix Emulate. You can change data table values while online.