Achieving High Availability with Redundant Rockwell ControlLogix Systems Rockwell’s Allen Bradley ControlLogix line supports enhanced redundancy with processors, communications, and power supplies to achieve high availability of your control system. Here are some of our recommendations, plus some pitfalls to avoid when implementing such a system. 1. Make sure you…
Process Solutions Technical Bulletins and Guides
A PID loop adjusts its OP to maintain its PV at its SP. Some PID loops cannot be satisfactorily tuned by adjusting the three primary constants. When combined with good basic tuning, advanced methods can improve stability, responsiveness, and limit overshooting. See The Basics of Tuning PID Loops for suggestions on…
The art of tuning a PID loop is to have it adjust its output (OP) to move the process variable (PV) as quickly as possible to the set point (responsive), minimize overshoot, and then hold the variable steady at the set point without excessive OP changes (stable). Definitions PID = Proportional,…
Hazardous Area Classification Guide The National Electrical Code (NEC) defines hazardous locations as those areas “where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or ignitable fibers or flyings.” Hazardous locations are classified in three ways by the NEC: type, condition, and…
Oval Gear Flow Meter Installation & Troubleshooting Knowing the do’s and don’ts of oval gear flow meter installations is just as important to the life of your meter as was the selection criteria for choosing an oval gear flow meter. To avoid any unintentional damage to your new oval gear…
Guide to Selecting an Oval Gear Meter Once you’ve decided that an Oval Gear Meter is the best flow meter for your specific application, there are a few key things you will need to know to narrow your selection down to a single oval gear flow meter. What is the…
Flow Measurement: The Truth About Upstream and Downstream Pipe Diameters Our experts agree that the most common issues with flow measurement are incorrect sizing of flow meters and poor installation. We’ve seen some pretty creative flow meter piping that totally neglect installation best practices. To ensure that doesn’t happen to…
If you spend much time working with calibration gas, it’s very likely that you will see the term “LEL” used extensively. LEL, short for “Lower Explosive Limit“, is defined as the lowest concentration (by percentage) of a gas or vapor in air that is capable of producing a flash of…
Instruments should be ranged to measure not only expected values but all values the system can produce. During upsets, actual values often exceed 20mA values for instruments tightly ranged for normal process conditions. For instruments with linear scale and additional capacity, the fix is simple: increase the 20mA scale on…
How to Use Wireless Technology in an Industrial Environment Let’s say you have a project where you need to get some information (sensor readings, video, alarms, etc) from one side of your facility to the other. Twenty years ago, you would install a new cable tray or dig a trench…
How to Optimize Equipment on a Low Pressure Tank When setting up a low pressure storage tank, there are a number of safety devices needed to ensure the protection of your tank including an ERV (Emergency Relief Valve), a PVRV (Pressure and Vacuum Relief Valve) and a BGR (Blanket Gas…
How to Size Pneumatic Actuators Pneumatic actuators come in many design types, but all share the same need for basic understanding of how their torque operates a valve. Whether you size a valve yourself, or you get someone else to do it, accuracy is critical. Incorrectly sizing an actuator can…
