Posts Tagged UE
Eight problems with outdated, electromechanical switches and eight solutions that will come with a digital upgrade to your plant.
The Problem: Unless tested on a regular basis, there is no way to determine when a problem exists. With mechanical switches, the only way to diagnose a problem is to remove the switch, leaving the control or safety function
Solution: Newer digital switches have an LCD screen that shows local process variable measurements and integrated internal diagnostics directly on the screen. You can easily monitor the health of the device at a glance, without having to remove the switch from operation.
The Problem: Mechanical switches require careful adjustments for reaching desired setpoints. Additionally, once these adjustments are made, settings
Pressure switch deadband isn’t an unknown, but neither is it a known value when you take a new switch out of its shipping box.
Experienced users will tell you that three identical units of the same pressure switch can have three different deadbands. All three switches will trip at the same pressure setpoint, but reset at different points. To complicate matters, the deadband reset point changes with the pressure setpoint. And, they’ll also say, there’s no way to know, out of the box, what the deadband is without applying pressure and checking.
Who cares about deadband? Not everyone. The exact deadband reset point is critical in some applications, and inconsequential in others.
Why is getting a known, repeatable deadband such a challenge with conventional electromechanical pressure switches, and is there anything to be done about it?