ControlPro v3.4
Variables are a setting on a PLC. More specifically, they are numbers assigned to different inputs/outputs on the PLC itself. The variable number tells the PLC which output to activate, which turns on pumps, conveyors, and valves for a specific storage container. Usually, each material has its own variable. If you have the same material in different storage containers, then it’s possible for one material to have more than one variable.
The variables in ControlPro can be found in the system screen. Click on the system and scales list to open a list of your systems.
In the list, double click on the system you want to access.
In the system screen, go to the materials tab. Inside the material tab is another tab labelled “automated materials”. Under the automated materials tab is a column labelled “Selected Var”. This is where you can find the variables assigned to each material.
In our example, we’ll look at the material “20-0-0 Nitrogen” with a variable of 21. To change a variable, click on the drop down under the var column associated with your material. When the drop-down menu appears, you can select the new variable. Keep in mind that each variable can only be used once. Make sure to click save after updating the variable.
We’ll cover a couple of scenarios to help you understand how to handle variables. One example is for two materials sharing a container, and one material in multiple containers.
In the first scenario, let’s say we have one material that is in two containers. Each container has its own pumps, valves, and variable number. If you want to switch between both containers, you’ll list the material twice, each with its own variable. Check the active box on the one you want to use. If the container runs out, you deactivate the one variable and activate the other. Then click save. You can only have one material per variable, and one variable per material, active at one time.
In the second scenario, there are two materials using the same container and same variable. Or perhaps, you want to repurpose a container for another material. In this case, you’ll give both materials the same variable. Whichever material is currently in the container is the material you’ll make active. When you need to switch to the other material, deactivate the one material and activate the other. In this example, I’m using Nitrogen and Phosphorus with the same variable. Nitrogen is marked as active. If I want to switch it to Phosphorous, check it as active, and check Nitrogen as inactive. Then click the save button.
You can rename the variables to make them easier to identify. Use the description field under the VARs tab to name your tanks, bins, hoppers, etc.
Once you add a description, the display name changes on the drop-down menu in the VAR column under the automated materials tab. Instead of handling variables directly, this makes it much easier to identify the storage unit.
If a variable is missing, you can add it yourself following these steps. Go to the VARs tab in the system window under the Materials tab. Double click on the blank line at the bottom. This activates the drop-down menu for selecting the meter. Once selected, then add your variable number under the VAR index column. Double click that field to type in the variable number. Once done, click save.
That’s a quick overview of variables. If you still need assistance, use our support site to create a support ticket.
In v3.3 of ControlPro, we’ve added the ability to create meters and variables directly in ControlPro. These are locked behind the admin account and require a representative from Murray to set this up. The end user can select from a list of prepopulated variables.