Pressure Control Loop Wiring Connections
This pictorial diagram shows the wiring connections for a simple pressure control loop, where a loop- powered 4-20 mA pressure transmitter sends a signal to a Honeywell controller, which in…
pH Transmitter Problem
A newly-installed pH transmitter does not seem to be measuring the pH of the process liquid accurately. The indicating controller’s display does not match the display of the hand-held pH…
Types of Cable Trays – Purpose, Advantages, Disadvantages
Cable tray systems are alternatives to wire ways and electrical conduit, which completely enclose cables. Cable trays are capable of supporting all types of wiring: such as High Voltage Power…
Current-to-Pressure Transducer Calibration Table
Suppose you wish to calibrate a current-to-pressure (“I/P”) transducer to an output range of 3 to 15 PSI, with an input range of 4 to 20 mA. Complete the following…
Analysis of HART communicator and Smart HART Transmitter
During the 1980’s the Rosemount corporation developed a means for 4-20 mA analog signaling circuits to carry digital signals as well, so that 4-20 mA process transmitters could be equipped…
Instrument Errors – Zero, Span, Linearity
Suppose an electronic pressure transmitter has an input range of 0 to 100 PSI and an output range of 4 to 20 mA. When subjected to a 5-step up-and-down “As-Found”…
Identify Instruments in Piping and instrumentation Diagram
Identify the meanings of the following instruments in this Piping and instrumentation Diagram (P&ID). Piping and instrumentation Diagram Solution: The below Piping and instrumentation (P&ID) Diagram shows the abbreviations or…
Differential Pressure Transmitter Questions
Connect a loop-powered differential pressure transmitter to a DC voltage source, a milliammeter, a 250 ohm resistor, and a diode as shown in the below figure. Differential Pressure Transmitter …
Alarm Annunciator Circuit with Acknowledge
Explain how the following annunciator circuit works: Note the jumper options shown in the diagram: one set of jumper positions configures the alarm for a process switch that alarms when…
Identify Process Variables in P&ID
Identify Process Variables in P&ID as they apply to the level controller shown in this P&ID (LIC 135), controlling the level of liquid in the horizontal receiver vessel: Process Variable…
