Introduction to ControlLogix Counters (CTU and CTD) We use ControlLogix Counters (CTU and CTD) to count transitions of a rung. More specifically, to count the false to true transition of a rung. We can use this to count pallets on a conveyor using a photo eye or proximity switch. Read More »
Introduction to ControlLogix Timers ControlLogix timers are used to delay events, or to time events. There are three timers in the ControlLogix processor. The TON (Timer On Delay) delays an event from turning on. Next, the TOF (Timer Off Delay) Delays an event from shutting off. Then we Read More »
Introduction to Interlock Bits (Internal Bits) If you are not familiar with basic instructions yet, please visit the post on how basic logic works. Interlock bits are tags in the processor that represent the fact that a certain condition has been made. For example: If all guard gates are Read More »
Introduction to the One Shot Instruction (ONS) The ONS instruction is used to trigger an event. It allows logical continuity for one scan when the instruction is true. After this, the instruction goes false until it is shut off (reset). The ONS instruction is commonly used with Latch/Unlatch Read More »
Introduction to Latch Logic The Latch/Unlatch instructions are retentive. This means that once the latch instructions goes true, the bit remains ON. Even when the instruction goes false, the bit will still remain a 1 until we unlatch the bit. Also, if we take the processor to program mode, Read More »
Introduction to Seal Circuits Seals and latches allow you to momentary press a button to energize an output. The output stays on until you press another button to shut the output off. There are some dangers associated with the latches that we will also discuss. If you are Read More »
Introduction to Basic ControlLogix Instructions An easy way to learn Basic ControlLogix Instructions is to understand how to convert logic to English. Before we do this, we need to understand three basic instructions: XIC, XIO, and OTE. The XIC (Examine if Closed, or Examine On) instruction can look at any Read More »
Introduction to ControlFlash ControlFlash is a firmware update utility. When replacing modules in a ControlLogix system, the program is configured to look for a specific revision of a module. When you replace a module, you may need to use ControlFlash to update the module’s firmware. The firmware Read More »
Introduction to Ethernet Communication Ethernet Communication is probably the most common protocol used in Industrial Automation. Ethernet communication has been a standard since around 1983, and allows computers to connect to each other over a local area network. When computers are connected to a network, they can share files, Read More »
Introduction to Passing Parameters to Subroutines We’ve already discussed simple subroutines. In most cases, subroutines are just used for the purpose of organization. Now, we will use subroutines as functions. We will create a subroutine that converts Celsius to Fahrenheit. Once we create the subroutine, we will use Read More »
