Kim-1 Scan Based Timer

Introduction to the Kim-1 Scan Based Timer In this post, I’ll cover some code I wrote for a Kim-1 Scan Based Timer. You can calibrate this timer by changing the number of loops, or by adding NOP instructions to get it just right for your application. I put this timer Read More »

Kim-1 (UNO) Scan Timer

ControlLogix Watch Window

Introduction to the ControlLogix Watch Window The ControlLogix Watch Window allows you to monitor tags from the current routine. You can also create a custom “Quick Watch” window to monitor any tag in the processor as you monitor the routine’s latter logic. This is very helpful when troubleshooting. Especially when Read More »

ControlLogix Watch Window

ControlLogix Processor Status Flags

Introduction to ControlLogix Processor Status Flags ControlLogix Processor Status Flags will tell us when certain events occur during our instruction execution. In this section, we’ll discuss the purpose of each of these status flags, and how we might use them in our logic. It’s important to realize that you will Read More »

ControlLogix Processor Status Flags

ControlLogix I/O Not Responding

Resolving ControlLogix I/O Not Responding If you have ControlLogix I/O Not Responding, you will have a blinking green I/O light on the processor. Additionally, while you are online, you will see “I/O Not Responding” in the online toolbar. The newer processors have an alphanumeric display which could give you some Read More »

ControlLogix I/O Not Responding

ControlLogix Rung True but No Output

Solving when a ControlLogix Rung is True but No Output It’s frustrating when a ControlLogix Rung True but you have No Output. In this section we’ll go over the causes for this, and how to correct them. It’s important that the processor is just doing what it’s told. We just Read More »

ControlLogix Rung True but No Output

ControlLogix Branching in Ladder Logic

Introduction to ControlLogix Branching in Ladder Logic ControlLogix Branching in Ladder Logic allows us to create “OR” Statements. Sometimes getting a branch on the right place in a rung is tricky for beginners. In this post, we’ll take a closer look at branching, We’ll discuss different ways to set up Read More »

ControlLogix Branching in Ladder Logic

Imsai 8080 Replica Build

Introduction to the Imsai 8080 Replica Build The Imsai 8080 Replica Build went very smoothly. I’ve always wanted one of these units. The quality of the parts were very good, and I have to say the pictures you see do not do it justice. It’s best to see one in Read More »

IMSAI 8080 Replica Build

Kenbak-1 Relative Jumps

Introduction to Kenbak-1 Relative Jumps Kenbak-1 Relative Jumps will jump to a location relative to the program counter. Really, there is no relative jump instruction. Therefore, if we require a relative jump we will do this with the JPI (Indirect Jump) instruction. The advantage of relative jumps is that we Read More »

Kenbak-1 Relative Jumps

Kenbak-1 Two Byte Addition

Introduction to Kenbak-1 Two Byte Addition With the Kenbak-1 Two Byte Addition, we can add larger numbers. Keep in mind that with 8 bit addition, we can only have numbers up to 377 octal (255 decimal). That’s if we don’t even used signed values. This is very limiting. When we Read More »

Kenbak-1 Two Byte Addition

Programming Loops on the Kenbak-1

Introduction to Programming Loops on the Kenbak-1 When Programming Loops on the Kenbak-1, we will use the JPD instruction. Basically, we set a register to a specific value. For this example, we’ll use the X register. Every time our loop executes, we decrement the X register. When the X register Read More »

Kenbak-1 building loops