Make the Right Choice Before Installation
Selecting the correct instrument is just as important as installing it correctly. A properly selected sensor improves measurement accuracy, extends service life, and minimizes maintenance costs.
This guide provides practical recommendations for choosing and installing flow, pressure, temperature, and level instruments in industrial applications.
Flow meter
| Parameter | Description |
|---|---|
| Fluid Type | Water, oil, gas, chemicals, compressed air, steam |
| Conductivity | Required for electromagnetic flow meters |
| Pipe Size | DN10–DN3000 depending on application |
| Flow Range | Minimum, normal and maximum flow |
| Pressure | Operating and maximum pressure |
| Temperature | Process temperature |
| Viscosity | Especially important for oils and high-viscosity liquids |
| Output Signal | 4-20mA, Pulse, RS485, Modbus, PNP/NPN |
| Power Supply | 24VDC, 110VAC, 220VAC |
Recommended Products
| Application | Recommended Product |
|---|---|
| Conductive Liquids | Electromagnetic Flow Meter |
| Clean Water | Turbine Flow Meter |
| Hydraulic Oil | Gear Flow Meter |
| Steam & Gas | Vortex Flow Meter |
| External Pipe Measurement | Clamp-on Ultrasonic Flow Meter |
| Compressed Air | Thermal Mass Flow Meter |
Pressure Measurement
| Parameter | Description |
|---|---|
| Pressure Range | Vacuum, Gauge or Absolute Pressure |
| Maximum Pressure | Overpressure capability |
| Medium | Gas, Liquid, Steam, Oil |
| Process Connection | G1/4, G1/2, NPT, Flange, etc. |
| Wetted Material | SS304, SS316L, Ceramic |
| Output Signal | 4-20mA, 0-10V, PNP/NPN, Relay |
| Power Supply | 24VDC, 110VAC, 220VAC |
| Protection Rating | IP65, IP67, IP68 |
Choose the appropriate pressure instrument according to your application.
| Application | Recommended Product |
|---|---|
| Hydraulic Systems | Pressure Transmitter |
| Water Supply & Pumps | Pressure Transmitter |
| Air Compressors | Electronic Pressure Switch |
| Pneumatic Equipment | Compact Pressure Sensor |
| Boiler & Steam Systems | High-Temperature Pressure Transmitter |
| Refrigeration & HVAC | Pressure Switch |
| Chemical Processing | Stainless Steel Pressure Transmitter |
| High Pressure Test Bench | High Pressure Transmitter |
Temperature Measurement
| Parameter | Description |
|---|---|
| Measuring Range | Operating temperature |
| Sensor Type | PT100, PT1000, Thermocouple |
| Accuracy | Class A, Class B |
| Probe Length | Immersion length |
| Probe Diameter | 3 mm, 6 mm, 8 mm, etc. |
| Process Connection | Thread, Flange, Compression Fitting |
| Output Signal | Resistance, 4-20mA, 0-10V |
| Protection Rating | IP65, IP67 |
Level Measurement
| Parameter | Description |
|---|---|
| Medium | Liquid, Oil, Powder, Slurry |
| Tank Height | Measuring range |
| Process Temperature | Operating temperature |
| Process Pressure | Tank pressure |
| Foam | Heavy or light foam |
| Vapor | Steam or condensation |
| Mounting Position | Top, Side, Bottom |
| Output Signal | 4-20mA, RS485, Relay |
Recommend
| Application | Recommended Product |
|---|---|
| Water Storage Tanks | Ultrasonic Level Sensor |
| Chemical Tanks | Radar Level Meter |
| Hydraulic Oil Reservoirs | Magnetostrictive Level Sensor |
| Fuel Tanks | Float Level Sensor |
| Wastewater Tanks | Ultrasonic Level Meter |
| High Temperature Liquids | Guided Wave Radar |
| Powder & Bulk Solids | Radar Level Meter |
| Pharmaceutical Tanks | Capacitive Level Sensor |
Installation Guidelines
Flow Meter Installation
Straight Pipe Requirements
Maintain sufficient straight pipe length to ensure stable flow conditions.
Upstream: 10D
Downstream: 5D
(D = Pipe diameter)
For vertical installation, ensure the flow direction is from bottom to top. Downward flow may result in a partially filled pipe, causing fluctuations in flow meter readings.
Avoid installation in the following locations:
- Pump outlets (if necessary, maintain a distance of at least 30D–50D from the pump; ultrasonic products, in particular, must be kept well away from pumps)
- Near elbows
- Near valves
- At pipe reducers or expanders (if installation is required, allow for 30D upstream and 10D downstream)
Installation Location
Recommended:
✓ Horizontal piping
✓ Pipe running full
✓ Stable flow direction
Avoid:
✗ Air pockets/cavitation
✗ Emptying of the pipe
✗ Severe vibration
✗ Strong electromagnetic interference
Pressure Sensor Installation
- Installation requirements for pressure tapping points:
- Keep away from pump pulsations
- Keep away from pressure spikes/surges
- Locate below steam lines (use a condensate loop/siphon if necessary)
- Ensure a proper seal
- Do not apply excessive torque during installation.
- If using a flush-diaphragm type, ensure the diaphragm does not bottom out.
Temperature Sensor Installation
- For optimal accuracy:
- Ensure an immersion depth of at least 6 times the probe diameter.
- Avoid installation in dead zones or areas with stagnant flow.
- Ensure good thermal contact.
- Use a thermowell (protective sleeve) if removal during operation is required.
Level Sensor Installation
- Keep the sensor away from:
- Tank inlets
- Agitators
- Ensure sufficient clearance around the measurement path.
- For probe-type level meters, be mindful of the blind zone and ensure the probe does not touch the bottom.
Troubleshooting Guide
| Problem | Possible Cause | Recommended Solution |
|---|---|---|
| No output signal | Incorrect wiring or insufficient power supply | Check wiring according to the manual and verify supply voltage. |
| Unstable readings | Air bubbles, pipe vibration, or electrical interference | Remove air pockets, reduce vibration, and use shielded cables. |
| Reading is lower than expected | Flow meter installed too close to an elbow, valve, or pump | Ensure adequate straight pipe lengths (typically 30D upstream, 10D downstream). |
| Reading is higher than expected | Incorrect flow range selection or improper calibration | Verify the selected measuring range and recalibrate if necessary. |
| No flow detected | Pipe not completely filled or flow direction reversed | Ensure the pipeline is full and the flow direction matches the arrow on the sensor. |
| Pressure reading fluctuates | Pump pulsation or pressure surges | Install a snubber or relocate the pressure sensor away from the pump outlet. |
| Temperature responds slowly | Insufficient insertion depth or poor thermal contact | Increase immersion length and ensure the probe contacts the process medium properly. |
| Level measurement is unstable | Foam, turbulence, agitators, or filling stream interference | Install the sensor away from the inlet and agitator, or select a more suitable measuring technology. |
| Communication failure (RS485/Modbus) | Incorrect address, baud rate, or cable wiring | Verify communication parameters and cable connections. |
| Frequent alarms or false switching | Incorrect switch point settings or unsuitable sensor selection | Adjust switching parameters or choose a sensor better suited to the application. |
We're Always Here to Help
Not every application fits a standard guide. If you're unsure about product selection, installation, configuration, or troubleshooting, don't hesitate to contact our engineering team.
Whether you're using a HONNO instrument or another brand, purchased from us or elsewhere, we'll gladly share our technical experience and help you find the best solution.
Because solving your process challenges is more important than making a sale.