In this episode, we’re looking at how you can emulate your projects within a local environment. RSLogix 500 Emulate allows you to load your complete programs and run them just like they would on a real PLC system.
This tool is particularly useful for those who can’t get their hands on expensive Allen Bradley equipment. I highly recommend using this environment for learning as well as development purposes.
In terms of programming, we’re going for a fairly simple program which was requested on a PLC forum. The program will turn on a stirrer for 5 minutes, wait for 55 minutes then repeat the cycle. Straightforward, but can be implemented in many different ways!
- RSLogix 500
- RSLinx Classic
- RSLogix Emulate500
Establishing a Connection in RSLinx Classic
If you have previously connected to a standard PLC, RSLogix is a tool you’ve used to. However, I was surprised to see that you do need to use it for the Emulate500 software as well.
After you have installed Emulate500, you need to add a special driver to RSLinx. Here’s a screenshot of the driver which you need to add into your definitions.
- Select the “Communications” tab.
- Select the “Configure Drivers…” option.
The window displayed at this point should contain a drop-down menu at the very top. Click the menu and select “SLC 500 (DH485) Emulator Driver”.
At this point, if the button “Add New…” next to the drop-down menu is greyed out, it means that you already have this driver. You may only have a single instance of it at a time. If it’s not the case, press the button to add the driver. You may choose a name for your driver at this point as well.
Lastly, during the creation process, you will be prompted to enter a “Station Number”. This will be a default assignment for your computer which will run the emulation. Set this value to 00 as the default.
Creating a basic RSLogix 500 Application to Test
You must create & use an RSLogix 500 application which compiles and validates without any errors. If you attempt to load an incomplete or erroneous program into RSLogix Emulate500, it will throw an error. You may not launch it without loading an application first.
For the purpose of this tutorial, we will be building a simple application which was requested on one of the PLC forums I follow on a regular basis.
Energize a VFD through a digital signal during a 5 minute period. De-energize the same VFD for 55 minutes. Continuously cycle the VFD on a 60-minute cycle.
There are many ways to program this simple ladder logic. However, I decided to stick to a single timer. Here’s the entire program:
In a few words: rung 0000 has a timer which will continuously increment to 60 minutes. Rung 0002 will reset the timer as soon as it reaches the 60-minute mark allowing it to restart. Rung 0001 will take care of energizing the motor starter (or VFD) which is connected to the first output of our PLC. Through the LIM instruction, the output is energized exclusively from 0 minutes to 5 minutes on the timer.
Instantiating an RSLogix Emulate500 Instance
Once you are happy with the program and it passed the RSLogix500 “Verify Project” (button in the top bar) check, it’s ready to be embedded into our emulation software.
Launch an instance of RSLogix Emulate500 and hit the “Open” button.
At this point, you need to navigate into the directory you’ve saved your program in and select the file.
You will be presented with a menu which allows you to select a few options with regards to the execution of your file. By default, your program will be running from the #2 Ladder. This is the default on a typical PLC as well. Furthermore, you can restrict the rungs you are looking to test by changing the start/stop limits.
An important field you should pay attention to is called “Station #”. This field will be in charge of selecting the virtual slot your PLC will reside in. In simple terms, every simulation you want to run in parallel with the others needs to have a unique identifier. If you aren’t running anything else, it would be a good idea to start with “01” (your PC is 00).
Now, all you need to do is hit the “RUN” button. Your application should now be live.
Go Online with the Virtual Processor
Switch back to your RSLogix 500 instance and go online with the virtual processor just like you would with a regular one. For some reason, you still need to “Download” your program the first time. Once online, you can navigate the program just as you would a regular PLC.
Conclusion on RSLogix Emulate500
I haven’t used this tool until recently when I had to test a few simple bits of logic. It is extremely useful for that purpose and I was pleasantly surprised that it worked without any issues.
Let me know what you think,