PLC programs scan usually from left to right, top to bottom. The outputs from the previous rung are available for the next. This is the operation of a PLC. Program control instructions allow us to add or remove parts of our program during each scan of the controller. The Horner APG XL4 has subroutines which we can achieve this control. We will look at how to divide your main logic up and at how subroutines work. Continue Reading!
We program the Horner XL4 OCS all-in-one controller by using Cscape. We will now use our Cscape software to establish communication. Last time we customized Cscape with icons to make it easier to find, communicate and control the unit. There are two different ways to communicate to the XL4 OCS controller, Ethernet and Serial. There are several different methods within these two ways that the XL4 will communicate. The Cscape software package will communicate both of these ways. We will look at establishing communication using Ethernet, USB (Serial) and Serial RS232.Another two serial ways to communicate would be RS485/RS422 (Serial) and CAN Bus (Serial). These two methods allow multiple controllers connected to the communication network. This is similar to Ethernet. Continue Reading!