Industrial Instrumentation

This lecture introduces temperature as a critical industrial measurement and explains temperature analog gauges, RTDs, thermocouples, and temperature transmitters for PLC-based monitoring.

Learn how temperature analog gauges provide cost-effective, mechanical, power-free readings (0–250°C) at non-critical points, with versatile scales and materials, including spiral designs for safe access and backup at critical points.

Explain how RTD, a resistance temperature detector, converts temperature into a resistance signal. Show how rising temperature increases metal resistance and reduces electron flow, producing the output ohms.

Explore RTD types by material: platinum (Pt100/1000, most common and accurate with linear resistance), copper (susceptible to oxidation and soft), and nickel (cheaper but ages and loses accuracy).

Explore the basic parts of an RTD—the head, stem, protecting tube, and sensing element—and how wiring and output resistance are configured, including thread, flange, and adjustable-union variants for applications.

Examine real RTD field components, including thread-type head mounted Pt100 sensors, three-wire terminations, cable entry, and protective stems, plus NPT and flange RTDs for high-pressure applications.

Simplex RTDs use a single sensor with two, three, or four wires and may fail if damaged. Duplex RTDs add a sensor as backup, keeping HMI reading and preventing shutdowns.

Explore converting RTD readings to temperature using PT 100 resistance data, applying the simple RTD formula and a quick shortcut: subtract 100 and divide by 0.385.

Thermocouples enable high-temperature measurement by producing millivolt signals from dissimilar metals joined at a junction, unlike RTDs that output ohms, with the PLC converting them for display on the HMI.

Discover common thermocouple types (k, j, t, e, n, s, r, b) and how temperature range, environment, accuracy, and budget influence their best applications.

Explore how RTDs provide a linear resistance-to-temperature relation, while thermocouples produce non-linear millivolts and require reference charts (type K, type S) to convert millivolts to temperature.

Discover how a two-wire thermocouple with red positive and negative leads connects to a PLC or meter, transmitting millivolts for remote temperature monitoring through a protective thermowell.

Explore RTD vs thermocouple: RTDs deliver high accuracy and stable, linear responses from -200°C to 500°C; thermocouples offer wider ranges and rugged durability, but with lower accuracy.

Learn to read RTD and thermocouple data sheets to procure spares, and identify sensor specs, line materials, process connections, and tag numbers.

Install a thermowell to protect RTD or thermocouples by housing the sensor in a protective tube welded to pipe, shielding it from high flow and corrosive or abrasive process fluids.

Explore how temperature transmitters convert RTD or thermocouple signals into standard 4–20 mA or 0–10 V outputs for PLCs, enabling remote monitoring via HMI with improved signal integrity and accuracy.

Discover head-type, field-mounted, and rail-mounted temperature transmitters, loop-powered 24 v dc, producing 4–20 mA for PLC monitoring with RTD and thermocouple sensors.

Connects a temperature transmitter with RTD or thermocouple sensors to generate a 4–20 mA signal and send it to a PLC and HMI for remote monitoring.

Learn to troubleshoot temperature sensors and transmitters by diagnosing RTD faults, damaged cables, and PLC or process discrepancies, using ohmmeter checks, continuity tests, and proper calibration.

Check continuity across the thermocouple’s negative and positive terminals to assess health, then measure millivolts if possible and use the type k reference table to convert to temperature.

Troubleshoot a temperature transmitter by verifying RTD resistance and calculating 4–20 mA output for a 0–100 °C range, then measure current in series and check PLC wiring and range settings.

Explore pressure and temperature as key industrial measures. Learn about pressure analog gauges, pressure switches, and pressure transmitters, including differential pressure transmitters for flow, level, and pressure.

Explore how pressure analog gauges operate mechanically without electricity, including diaphragm, capillary, and bowden-tube types, their use at non-critical points, and how they compare to digital instruments.

Explore atmospheric, gauge, and absolute pressure, learn how gauge readings exclude atmospheric pressure, how absolute pressure includes vacuum, and how engineers choose measurement types in industries.

Pressure switches serve as digital instruments with built-in sensing elements that act as on/off switches via a relay, enabling safety interlocks and adjustable set and reset points.

Showcases how a pressure switch uses NC and NO contacts to drive a contactor, shifting the common output from NC to NO at the set pressure to control a motor.

Pressure transmitters measure pressure and convert it into 4 to 20 milliampere or 0 to 10 volt signals for PLCs, enabling real-time monitoring via the HMI.

Explain how pressure transmitters convert pressure to electrical signals through sensor transducers and transmitters, covering strain gauge, diaphragm, capacitive, and potentiometric types and 4 to 20 milliampere outputs.

Explore the parts of a pressure transmitter, including field mounted and pencil types, tag plates, diaphragms, digital display, and two-wire loop connections, and learn calibration basics.

Learn how capillary tubing pressure transmitters protect instruments from high temperatures, enable accessible calibration and maintenance, and weigh advantages against drawbacks like length-related output inaccuracy and slower response times.

Explore pencil type, field mounted, and flange type pressure transmitters, noting space constraints, leakage risks of threaded connections at high pressure, and devices with 4-20 mA or 0-10 V outputs.

Discover pencil type pressure transmitters for tight spaces in hvac chillers and compressors, featuring a diaphragm sensor, 4 to 20 mA loop-powered output, and two-wire 24 v dc installation.

Select a transmitter with a range around 20–25% above the process pressure. Also verify input/output compatibility, accuracy, temperature, sensing material, and rated operating pressure, safe operating pressure, and burst pressure.

Explore how to read a pressure transmitter datasheet, extract key specs like pressure range, materials, output, and installation details to select, procure, and mount a transmitter.

Understand static pressure in differential pressure transmitters, and why you must specify the system’s static pressure to the vendor to prevent damage when high and low side pressures differ.

Define the turn down ratio as the max-to-min measurable value of an instrument, and illustrate how a 0–20 bar transmitter with a 1:10 ratio yields a 2 bar minimum reading.

Choose between metal and ceramic diaphragms for pressure transmitters based on application, pressure range, corrosion resistance, and potential spikes, balancing elasticity, brittleness, durability, and cost.

Explore differential pressure transmitters with high and low pressure ports, converting delta P to a 4–20 mA output for level, flow, pressure, and density measurements.

Learn how level measurement manages tank inventory and prevents spills by using level switches and transmitters, including ultrasonic, radar, differential pressure, and magnetic level gauges.

Level switches provide on/off digital outputs for control, not actual level readings. They are used to maintain a tank at setpoints like 70 percent by driving a motor circuit.

Explore how float switches use buoyancy and a lever connected to a limit switch to control motor action as tank levels rise and fall, with 70% and 30% indicators.

Explore how a DP transmitter measures tank level by head pressure, considering dead level, open versus closed tanks, and proper high and low port installation.

Install a differential pressure transmitter at the tank bottom with the low side vented to atmosphere, set 0–12,000 mm water column using the fluid’s specific gravity for 0–100% PLC monitoring.

Open tank level measurement with a DP transmitter in zero suppression, calculating LRB and ERV from a 1 m vertical distance and a 10 m tank height with specific gravity.

Apply dry leg calculations with a DPI transmitter for a closed tank by subtracting the top gas pressure from the bottom liquid pressure to obtain the liquid head.

Demonstrate wet leg calculations for level measurement with a DPI transmitter in a tank, comparing wet and dry leg methods and deriving LLRV and UAV from height and specific gravity.

Explore boiler drum level measurement using differential pressure transmitters to safely and efficiently monitor water and steam separation, preventing tube overheating and potential ruptures.

Analyze factors influencing boiler drum level measurement with a DP transmitter, including wet leg, closed tank effects, and LRB/ERV calculations using p naught, DS, DN, H, and V.

Monitor boiler drum level as a safety application using a differential pressure transmitter that compares hp and lp pressures, with 4–20 mA signaling.

Learn to calculate the delta p and set the llrv and erv ranges of a dp transmitter for boiler level measurement using h min, h max, and wet-leg water density.

Master ultrasonic level transmitters, non-contact devices at the top of storage tanks that use piezoelectric sensors and 20 kHz to 200 kHz waves to calculate tank level from the echo.

Explore how ultrasonic level transmitters, like radar transmitters, measure tank level by time-of-flight using speed of sound, with a 12 m tank example yielding 58.625%.

Explore radar level transmitters, using non-contact electromagnetic waves and time-of-flight to measure tank level. Compare ordinary radar with guided wave radar, noting range, stability with foam, and maintenance considerations.

Use the Chrome online sizing tool to select a radar level transmitter for liquids, choosing media, transmitter type, and tank conditions, and generate a vendor quotation.

Explore flow as a measuring factor and compare various flow meters—positive displacement, electromagnetic, ultrasonic, Coriolis, vortex, and rotameters—focusing on selection and working principles.

Mass flow measures mass per time and is unaffected by temperature or pressure, while volumetric flow measures volume and requires compensation; thermal meters suit gases, Coriolis for liquids, volumetric cheaper.

Explain laminar flow as smooth, low-dissipation flow at low rates and with viscous fluids, and turbulent flow as chaotic, high-dissipation flow, then introduce Reynolds number for classification.

Maintain a straight pipe upstream and downstream around the flow meter to ensure laminar flow. Follow meter-specific straight-run values, such as 5x upstream and 3x downstream for magnetic meters.

Explore Coriolis mass flow meters—high accuracy for dense liquids and some gases—and thermal mass flow meters, with focus on working principle, selection, sizing, and installation.

Discover how a Coriolis mass flow meter uses a vibrating tube, exciter, and dual sensors to measure mass flow via phase shift and density, enabling volumetric flow calculation.

Learn about the coriolis flowmeter's sensor tube and transmitter head, and how the transmitter converts signals to 4 to 20 mA and displays a flow totalizer.

Demonstrates using Emerson's sizing tool to select a Coriolis mass flow meter for process conditions, including line size, wetted material, and fluid properties, and to generate a sizing report.

Extract the Emerson datasheet for sensor CMFS 007M, noting 0.1% mass flow accuracy across 15–30 kg/h with pressure drop rising to 1.14 bars; consult the process engineer for acceptability.

This lecture introduces thermal mass flow meters, used to measure natural gas and gas flow rates, with insertion or flange types and a probe featuring a heater and RTD sensor.

Operate a thermal mass flow meter by maintaining a constant delta t between the RTD and a self-heated heater, so changes in heater current indicate fluid flow.

Learn to install and configure a thermal mass flow meter with a transmitter, digital display, and remote monitoring, including center-of-pipe insertion, temperature and heater sensors, and rs485 (modbus) output.

compare coriolis and thermal mass flow meters in accuracy, maintenance, and cost; coriolis offers high liquid accuracy but high cost, while thermal meters suit gas, low flow, and insertion options.

Learn how volumetric flow meters measure flow in cubic meters per hour. Understand temperature and pressure compensation in electromagnetic, ultrasonic, rotor meters (variable area flow meters), and DPI transmitter considerations.

Learn how two electromagnetic coils create a magnetic field in a non-magnetic pipe; a conductive liquid induces voltage across electrodes per Faraday's law, which electronics convert to the flow rate.

Understand the electromagnetic flowmeter principle: a magnetic field induces voltage in conductive liquids, measured by electrodes to determine flow; learn interference suppression with pulsed direct current for stable accuracy.

Explore electromagnetic flow meters, focusing on totalizer readings for billing and the current flow rate displayed, plus installation details like ac power, grounding, and 4–20 ma or 0–10 v outputs.

Examine electromagnetic flowmeters, noting low energy use, no moving parts, easy installation, bidirectional flow, and broad turndown, alongside drawbacks like higher cost, non-conductive fluid limits, and susceptibility to electromagnetic interference.

Explore rotameters, or variable area flow meters, including analog and digital types, their working principle with a float in a tapered tube, and vertical installation in desalination plants.

Illustrates how a rotameter, a flow meter, measures fluid flow in a tapered tube using a float whose height, read on a calibrated liters-per-minute scale, reflects the flow rate.

Rotameters offer cheap, mechanical flow measurements using a float and scale. Digital rotameters enable remote PLC/HMI monitoring and a built-in totalizer with 24-V loop power.

Examine rotameters' low cost, simple design, minimal straight-run requirements, and low pressure drop, and discuss limitations like accuracy, fluid compatibility, and periodic maintenance, in laboratories and quality control environments.

Turbine type flow meters provide volumetric flow with temperature and pressure compensation, using a rotating turbine to measure flow; analog units show totalizers, while digital versions offer 4–20 mA outputs.

Measure flow with turbine type flowmeters that use magnet-equipped blades rotating as fluid flows; a pickup coil detects magnets to output square pulses, whose frequency is proportional to flow rate.

Turbine flow meters monitor water consumption using totalizers to show cumulative flow per plant. Digital meters deliver real-time flow rates, while mechanical turbines provide only total consumption readings.

Digital turbine flow meters deliver high accuracy for liquids (0.25–0.5%) and gases (~1.5%), with strong repeatability and PLC/HMI outputs. They require clean fluids, calibration, and straight runs for laminar flow.

Explore ultrasonic flow meters, a precise yet costly volumetric meter with accuracy comparable to Coriolis meters. Compare transit-time and Doppler styles and their use for clean or particulate fluids.

Transit time ultrasonic flow meters measure flow by time-of-flight between two sensors, offering precision in large pipes, but require clean fluids; for impurities, Doppler meters are used.

Use doppler ultrasonic flow meters for impure fluids, detecting frequency shifts from moving impurities; impurities must exceed 100 ppm and 100 microns, otherwise use transit-time meters.

Explore how a differential pressure transmitter measures flow by sensing pressure drop across an orifice. Apply Bernoulli's principle to relate this drop to volumetric flow.

Compare laminar and turbulent flow and use Reynolds number to predict flow regime, with laminar below 2000 and turbulent above 4000, using rho times v times d divided by mu.

Size the orifice plate for the DPI transmitter by evaluating viscosity, minimum/nominal/maximum flow rates, Reynolds number, vena contracta, and beta ratio to ensure accurate pressure drop.

Identify four orifice plate types—concentric, eccentric, segmental, quadrant edge—and their use for clean fluids, slurries, and viscous liquids, with installation choices and DP transmitter implications.

Identify the vena contracta, the smallest flow diameter, and show how locating it accurately enables correct pressure drop and flow rate calculations for dp transmitters and orifice design.

Master beta ratio in orifice sizing by understanding bore to outer diameter and its effect on pressure drop, with ranges 0.2 to 0.6 and 0.5 to 0.65.

The vent hole at the top of the bore prevents gas buildup, while the drain hole at the bottom avoids condensates, ensuring accurate differential pressure and flow readings.

Position impulse lines before the orifice to the high-pressure port and after to the low-pressure port, using bottom connections for liquids or steam and top for gases at 45 degrees.

Explain how a differential pressure transmitter converts pressure drop to flow with square root output, and when to use linear versus square root mode to avoid double conversion.

Convert differential pressure to flow by calculating linear milliamperes, deriving square root milliamperes, then converting to flow using the set flow range.

Size the orifice plate with the Daniel orifice flow calculator, an online DP transmitter sizing tool by inputting flow type, fluid properties, pipe size, beta ratio, and differential pressure.

Explore calibration in industrial instrumentation, including temperature, pressure, level, and flow transmitters. Learn why yearly or half-yearly calibrations ensure accurate process measurements and reliable data reconciliation.

Learn how calibration relies on a reference block and a reference meter to ensure instruments read the correct value when tested with known weights.

Rearranging instrument ranges aligns output to the set span, showing how changing from 0–500 to 0–1000 shifts the 4–20 mA signal; always match LRB and ERV with PLC for accuracy.

Master zero trim and zero spanning by calibrating instruments to read zero with no process value and to read the maximum span, as shown by a weight scale example.

Learn to use hart communicators to bring transmitters online, configure, calibrate, and troubleshoot instrumentation, covering emerson hart models 275, 375, 475, and telex and how to connect them.

Connect a heart communicator to the instrument, determine whether it is loop powered or a retransmission device, and use a 250 ohm resistor to convert 4-20 mA to 1-5 V.

Explore temperature transmitter calibration by setting LRB/ERV, selecting RTD or thermocouple sensors, configuring 4 to 20 mA output, and calibrating online via a heart communicator for PLC integration.

Discover how to calibrate a temperature transmitter fed by RTD using ohm simulator, perform zero trimming at 100 ohms, and span trim to reach 4–20 mA for 0–200 °C.

Calibrate a temperature transmitter for a 0 to 1200 degrees Celsius range using a k-type thermocouple, zero and span trim, and millivolt signal with 4 mA and 20 mA checks.

Explore bench and field calibration of industrial pressure transmitters, using a digital master pressure gauge, heart communicator, and pressure source for zero and span trimming.

Learn to calibrate a differential pressure transmitter using a pneumatic DA3 tee setup, with a pressure source, push fittings, and a master gauge to perform zero and span trim.

Zero-trim and span trim a pressure transmitter in a 0–8 bar range by adjusting calibration screws until zero pressure yields 4 mA, with a multimeter monitoring output.

Span trim a pressure transmitter by using the span button to set 20 mA at eight bars after zero trimming, ensuring proper calibration without heart communicator if supported.

Adjust the lower range value to 35 mm H2O to compensate for a damaged diaphragm, allowing the pressure transmitter to output four milliamperes at zero and align with the PLC.

Learn to calibrate a loop-powered pressure transmitter using a hart communicator, including zero trim, span trim, and a five-point calibration from 0% to 100% of range.

Calibrate dp transmitters for level, flow, and pressure monitoring using zero and span trimming, five-point calibration, and 4-20 mA outputs; distinguish linear vs square-root operation and external extractors.

Explain the operational sequence for three-way manifolds on a dp transmitter, including block valves, the equalizing valve, and safe in-service and removal steps.

Understand how a block and bleed valve manifold measures direct gauge pressure by opening the block valve to feed the transmitter, then venting with the bleed valve to remove transmitter.

Calibrate dp transmitters like pressure transmitters by applying pressure to the high side while the low side remains atmospheric, and read the 4 to 20mA loop using a hart communicator.

Zero trim a dp transmitter in service using a three-way manifold by closing lp valve, equalizing pressure, and trimming via screws or heart communicator to 4 mA and 20 mA.

Calibrate a differential pressure transmitter by switching its transfer function from linear to square root via a Hart communicator, enabling square root milliamperes for accurate flow measurement.

Calibrate a diaphragm seal DP transmitter for tank level by zero trimming when empty, then span using a pressure source across 0, 25, 50, 75, 100%.

Calibrate a DP transmitter for drum level by setting lower and upper ranges, keeping the lower impulse line filled, and using zero and span trim to verify 4–20 mA outputs.

Calibrate radar and ultrasonic level transmitters setting 0% and 100%, align LRP and ERV, then trim back and forth to verify 4 mA at zero and 20 mA at full.

Learn how to calibrate flow meters for accurate totalizer readings and material management using a bench test method with a calibrated weight scale and matching flanges.

Master zero trimming of a Coriolis flow meter by filling the tube with fluid, letting it settle, and trimming when the reading is not zero.

Calibrate a flow meter by comparing totalizer differences to a calibrated weight scale, and adjust scale factor (k factor) so outputs match within the meter's accuracy, issuing a calibration certificate.

Conduct a ten-minute run to compare flowmeter totalizer readings with a calibrated weight scale, calculate the error, and determine calibration needs. Recalculate the K factor and repeat until readings match.

Configure a Coriolis mass flow meter with a HART communicator, and connect two 50 ohm resistors in parallel across the 4–20 mA retransmission loop to calibrate cal factor for readings.

Explore the second method for flow meter calibration, using a reference flow meter in series, compare readings, compute relative error, and update the scale factor via a heart communicator.

Loop testing of transmitters verifies the measurement loop between instrument and plc, checks signal integrity, and validates 4-20 mA output in manual mode.

Dynamic adjustment trimming calibrates pressure transmitters in a 4–20 mA system to correct small deviations, improving accuracy from 4 mA to 20 mA across the 0–10 bar range.