ControlLogix SRTP Instruction

Introduction to the ControlLogix SRTP Instruction Generally, we use the ControlLogix SRTP Instruction for heating or cooling control. We’ll just concentrate on heating control for the first part of this post. that will keep things simple. In the second part of this post, we’ll discuss a heat/cool process. With heating Read More »

SRTP Instruction for ControlLogix

ControlLogix Rate Limiter (RLIM)

Introduction to ControlLogix Rate Limiter (RLIM) We use the ControlLogix Rate Limiter (RLIM) to slow the rate of change from a tag. For example, if the operator changes a setpoint, we might not want to feed the new setpoint directly to a PID. This could cause a large bump in Read More »


ControlLogix Lead/Lag Instruction (LDLG)

Introduction to the ControlLogix Lead/Lag Instruction (LDLG) The ControlLogix Lead/Lag Instruction (LDLG) is useful in PID Loops. We might use this with the FeedForward (FF), or Bias input. The purpose of the Feed Forward is to anticipate changes. For example, if our load changes, we can immediately offset the output Read More »


ControlLogix PID Training

Introduction to ControlLogix PID Training ControlLogix PID Training allows the students to understand certain areas of Process Control. PID is Proportional, Integral, and Derivative. For example, we have a heating system. The goal is to maintain a constant temperature. Good PID control returns the temperature back to the set point Read More »


Independent PID with ControlLogix

Introduction to Independent PID with ControlLogix In this section we’ll set up an Introduction to Independent PID with ControlLogix. Realize the equation is different than the dependent mode. For detailed information on the PID instruction, visit the ControlLogix Instruction Set Reference Manual. The PID instruction is in chapter 13. With Read More »


Tuning a PID for Tank Level

Introduction to Tuning a PID for Tank Level Tuning a PID for Tank Level has some challenges that are different than a standard PID tuning procedure. In the first place, a tank level is not self regulating. It’s an integrating process. In other words, if the system is slightly out Read More »

Tank Level

Troubleshooting PID Loops

Introduction to Troubleshooting PID Loops Indeed troubleshooting PID Loops can be frustrating. It can take time, patience, and knowledge of the process. In this section, we’ll look at a few common issues you might have with PID loops, and how to solve those issues. This is for example only, and Read More »

Derivative too high

Feed Forward for PlantPAx PID

Introduction to Feed Forward for PlantPAx PID With Feed Forward for PlantPAx PID, we can adjust the control variable directly. For example, if the load increases from a tank, we can immediately provide a higher setpoint to the inflow. This can drastically improve response time. Additionally, it will usually reduce Read More »

Disturbance Offset

Cascading PID with PlantPAx

Introduction to Cascading PID with PlantPAx In this section, we’ll cover Cascading PID with PlantPAx. We’ll do this by simulating a level in a tank. The tank controller will change the setpoint of a flow controller. The goal is to maintain a constant tank level. It’s important to realize that Read More »

Cascading PID

Tuning PlantPAx P_PIDE with Simulator

Introduction to Tuning PlantPAx P_PIDE with Simulator Before Tuning PlantPAx P_PIDE, please reset your simulator. This way, we’ll get back to a known configuration. To reset the simulator, use your test button until you get to the reset option. Then press Up then TEST again. In the last sections, we’ve Read More »

PID Settings