A transmitter is an electronic device that would convert the process variables such as frequency, pressure, temperature, and flow to a 4-20mA signal. So this device would convert the sensor input signals to a control signal which is capable to regulate the current flow. The 2,3, and 4 wire transmitters play a major role in …
Introduction Special-purpose electronic test instruments called loop calibrators are manufactured for the express purpose of 4-20 mA current loop circuit troubleshooting. These versatile instruments are generally capable of not only measuring current, but also sourcing current to unpowered devices in a loop, and also simulating the operation of loop-powered 4-20 mA transmitters. A very popular loop calibrator unit is the Altek …
How to Troubleshooting 4 -20 mA Current Loops with Loop Calibrator? Read More »
Introduction Before the age of electronic circuitry the whole process is controlled by mechanically.Facilities used pneumatic control signals where controllers were powered by varying pressures of compressed air.The 3 -15psi standard became the standard.Easier to differentiate a live zero (3 psi) signal from a failure in the system (0 psi).In the 1950s, as electronic systems became …
