Monnit Sensor Selection Guide Choose the Right Sensors for Temperature Water Equipment and Industrial Monitoring
Updated: 5 days ago
A good monitoring system starts with the measurement, not the gadget. The right Monnit sensor should answer a practical question: Is this cooler holding temperature? Is water where it should not be? Did that pump run? Is a machine drawing power when it should?
This catalogue-style guide breaks Monnit sensor selection into physical measurements, common applications, and the sensor types that usually fit best. Use it to plan a system made from the right mix of sensors plus a gateway that gets the data online.
Start by choosing what you need to measure
Monnit systems are useful because they separate the sensing point from the communications hub. Sensors sit where the condition exists. A gateway collects readings and sends them to the monitoring platform through Ethernet, Wi-Fi, cellular, or another supported connection, depending on the gateway model.
Think of the system in two parts:
System part | What it does | Selection question |
Sensor | Measures a physical condition or status | What condition needs to be tracked? |
Gateway | Receives sensor data and sends it online | What network connection is available at the site? |
Most projects need more than one sensor type. A restaurant may need refrigerator probes, water detection under sinks, and open or closed status on doors. A facility team may need temperature and humidity in mechanical rooms, current sensing on motors, and dry contact monitoring from alarms.
The fastest way to choose is to group sensors by measurement.
Temperature sensors protect products, rooms, and equipment
Temperature is often the first measurement people add because it is tied to product quality, safety, comfort, and machine health. The key choice is where the temperature must be measured.
Built-in temperature sensors suit general room and cabinet readings
Use a standard temperature sensor when the sensor body can sit in the same space as the air you want to track.
Good fits include:
Storage rooms
Server and network closets
Warehouses
Laboratory rooms
Unoccupied utility spaces
Enclosed cabinets where wireless signal can still reach the gateway
This type is simple to install. Mount the device away from direct sunlight, heater discharge, condensing moisture, or vibrating machinery. For room monitoring, place it where it sees representative air, not a hot or cold corner.
Temperature probes suit freezers, coolers, pipes, tanks, and tight spaces
A temperature probe places the sensing tip where the reading is needed while the wireless transmitter stays in a better mounting location. This is the right choice when the measurement point is wet, cold, sealed, or hard to reach.
Common probe applications include:
Walk-in coolers and freezers
Refrigerated display cases
Vaccine and medication refrigerators
Pipe surface monitoring
Liquid tanks where the probe is compatible with the medium
Food service cold storage
HVAC ducts or plenums when the probe style suits the installation
Probe selection matters. Match the probe to the environment, temperature range, and installation method. A freezer probe needs to tolerate low temperatures. A pipe or surface measurement needs solid contact and insulation from surrounding air. A liquid application needs a probe rated for that use.
Best choice when accuracy at a specific point matters: a probe sensor, not a general room sensor.
Choose alarm thresholds before installing
Temperature monitoring works best when the alert thresholds reflect the real process. A freezer does not need the same limits as a server closet. A cooler may warm briefly during loading, so alert timing can matter as much as the number.
Set thresholds for:
Application | What to watch |
Cold storage | High temperature, fast rise, door-related heat gain |
Server room | High temperature and HVAC failure patterns |
Pipe freeze protection | Low temperature near freezing conditions |
Equipment cabinet | Heat buildup when fans or ventilation fail |
Temperature and humidity sensors show comfort, condensation, and storage risk
Temperature alone does not explain moisture. Temperature and humidity sensors measure both conditions in the same location, which helps when the concern is condensation, mold risk, static control, drying, or product condition.
Use temperature and humidity monitoring for:
Mechanical rooms
Storage rooms
Document and archive spaces
Museums and collections
Greenhouses and grow rooms
Crawl spaces and basements
Server rooms where static or moisture may matter
Production areas with moisture-sensitive materials
Humidity readings can change sharply based on airflow and nearby surfaces. Avoid mounting the sensor directly above humidifiers, drains, exterior doors, or supply vents unless that is the exact location you mean to monitor.
Temperature and humidity monitoring is also useful as an early warning. A rising humidity trend in a basement may show moisture entry before standing water appears. A room that swings between dry and damp may need ventilation changes, not just an alarm.
Water detection sensors catch leaks before they spread
Water detection is one of the clearest monitoring wins. A small leak can damage flooring, inventory, electrical equipment, insulation, and finished walls. A sensor does not stop the leak, but it can shorten the time between first water and first response.
Monnit-style water monitoring generally fits two application patterns.
Spot water detection works for one likely leak point
Use a spot sensor where water will collect in a known place.
Good fits include:
Under a sink
Near a water heater
Below a condensate pan
Next to a sump pump
Behind a refrigerator or ice machine
Under a dishwasher
By a process water connection
Place the sensor at the lowest practical point where water would appear first. A sensor mounted too high or too far from the likely path may never see the leak.
Rope or extended leak sensing works for a larger risk area
When water could appear along a long edge or around a piece of equipment, use a rope-style or extended detection approach when available. This gives broader coverage than a single point.
Use it around:
Data room perimeter walls
Mechanical equipment pads
Raised floor areas
Long rows of refrigeration cases
Areas under pipe runs
Utility rooms with several leak sources
The selection rule is simple: use spot detection for one likely point and extended detection for spread-out risk.
Equipment status sensors tell you whether something changed state
Equipment status monitoring answers yes-or-no questions. Is a door open? Did a relay close? Is a machine running? Did a float switch trip? These sensors are helpful because many problems start as a change in state before they show up as temperature, humidity, or water.
Open and closed status works for doors, hatches, and panels
Use magnetic contact sensors or open and closed sensors when you need to know whether something moved from its normal position.
Common applications include:
Cooler and freezer doors
Exterior gates
Equipment access panels
Chemical storage cabinets
Hatches and lids
Tool cages or storage rooms
For cold storage, pairing a door sensor with a temperature probe gives better context. A high-temperature alarm means one thing if the door has been open. It means something else if the door is closed and the cooler is still warming.
Dry contact sensors connect to existing switches and alarms
Dry contact monitoring is one of the most flexible categories. It reads the state of a switch, relay, or contact output from another device. That makes it a bridge between existing equipment and the monitoring platform.
Use dry contact sensors for:
Float switches
Alarm relay outputs
Generator run signals
Pump fault contacts
Panel alarm contacts
Pressure switch outputs
Door interlocks
Machine ready or fault states
The sensor does not need to understand the whole machine. It only needs a clean open or closed signal from the equipment. That makes dry contact monitoring useful for retrofits, especially when replacing the equipment controls is not practical.
Activity and vibration sensing can show run time or movement
For some assets, the useful question is whether motion or vibration is present. A vibration or activity sensor can help show when equipment starts, stops, or behaves differently than normal.
Use this approach for:
Motors
Fans
Pumps
Compressors
Conveyors
HVAC equipment
This is not the same as full machine diagnostics. It is often enough for basic run status, run time tracking, or no-run alerts.
Electrical and industrial measurements extend the system
Some projects need more than environmental sensing. Electrical and industrial measurements help teams monitor panels, machines, process equipment, and utility loads. Selection depends on the signal type already available or the physical quantity you need to measure.
Current sensing shows load and run status
Current sensors monitor whether electrical current flows through a conductor. This is useful when run status matters more than the exact mechanical action.
Best uses include:
Confirming that a pump is running
Checking fan operation
Tracking compressor cycles
Watching heater operation
Detecting unexpected equipment power draw
Verifying that a machine shut down when expected
Current sensing is often non-invasive when it uses a clamp-style current transformer around a conductor. Installation still needs qualified electrical work where panels or live circuits are involved.
Voltage sensing shows presence or absence of power
Voltage monitoring helps answer whether power is available at a circuit, battery, panel output, or control signal, depending on the sensor model and supported range.
Use voltage monitoring for:
Power availability
Battery or DC supply status
Control circuit state
Panel output confirmation
Backup system monitoring
Match the sensor to AC or DC, the voltage range, and the installation method. Do not connect a sensor to a voltage it is not designed to measure.
Pulse counting works for meters and repeated events
Pulse counters track repeated contact closures or pulse outputs. They are useful with meters and equipment that produce a pulse for each event or quantity.
Common uses include:
Water meters with pulse output
Gas or utility meters with compatible pulse output
Production counts
Door cycles
Batch counts
Pump cycles
A pulse count becomes more useful when paired with reporting over time. For example, a water meter pulse count can show after-hours use that may point to a leak.
Analog inputs support industrial transmitters
Industrial equipment often outputs standard analog signals. Look for compatible Monnit input sensors or interface modules when the source signal uses formats such as:
4 to 20 mA
0 to 10 V
0 to 5 V
Resistive or thermistor-type signals when supported
Thermocouple or RTD temperature signals when supported by the chosen model
These inputs let a wireless monitoring system read from pressure transducers, level sensors, flow instruments, and other industrial transmitters. The key is compatibility. Match the signal type, range, wiring, power needs, and scaling in the monitoring software.
Match sensor type to the application
The table below gives a practical selection shortcut.
Application | Best sensor type | Why it fits |
Walk-in freezer | Temperature probe plus door status | Measures the cold space and explains warm events |
Server room | Temperature and humidity | Tracks heat and moisture conditions |
Water heater closet | Water detection | Catches leaks near a common failure point |
Sump pump area | Water detection plus equipment status | Detects water and confirms pump or float action |
Exhaust fan | Current or vibration sensing | Shows whether the fan runs |
Generator | Dry contact or current sensing | Reports run, fault, or load state |
Process tank | Probe or industrial analog input | Matches the measurement point or transmitter |
Utility meter | Pulse counter | Converts pulses into usage trends |
Equipment alarm panel | Dry contact input | Reads existing alarm relay outputs |
Warehouse storage | Temperature and humidity | Tracks broad environmental conditions |
Build the system with sensors plus a gateway
After choosing sensor types, select the gateway. The gateway is the connection point between the local wireless sensors and the online monitoring account.
Pick the gateway based on site conditions:
Gateway connection | Good fit |
Ethernet | Facilities with a reliable wired network nearby |
Wi-Fi | Sites where wireless network access is approved and stable |
Cellular | Remote buildings, temporary sites, or places without local network access |
USB or local connection options | Smaller setups or special configurations when supported |
Plan gateway placement before mounting sensors. Wireless range depends on walls, metal equipment, distance, interference, and building layout. Cold rooms, mechanical spaces, and metal cabinets can reduce signal strength. In larger facilities, more than one gateway may be the cleanest design.
A simple build process works well:
List the assets or areas to monitor.
Write the condition that matters for each one.
Select the matching sensor type.
Decide alert thresholds and alert timing.
Choose a gateway with the right network connection.
Test readings and signal strength before final mounting.
Label each sensor clearly in the monitoring platform.
This keeps the system practical. A sensor named `Freezer 1 Probe` is more useful during an alarm than a generic device name.
Plan alerts around response, not just measurement
A reading only helps if it leads to the right action. Build alerts around who can respond, how fast they can act, and what they need to know.
For example, a water sensor under a water heater may need an immediate text or email. A warehouse humidity alert may only need a daily review unless it crosses a critical limit. A freezer temperature alert may need a delay long enough to ignore normal door openings but short enough to protect inventory.
Good alert plans define:
Normal range
Warning range
Critical range
Delay before alert
Escalation contact
After-hours contact
What the responder should check first
Pairing sensors often improves decisions. Temperature plus door status, water detection plus pump status, and current sensing plus dry contact alarms all give better context than one reading alone.
A practical sensor selection checklist
Before ordering or installing, confirm these points:
The sensor measures the physical condition you care about.
The expected range fits the sensor model.
The mounting location gives a representative reading.
The environment suits the sensor body, probe, cable, or contact.
Electrical inputs match the signal type and range.
A qualified person handles wiring where required.
The gateway has a reliable network path.
Sensor names, thresholds, and alerts match real response steps.
A strong Monnit system is not a pile of devices. It is a set of clear measurements tied to real risks. Choose temperature probes for exact cold or hot points, temperature and humidity sensors for room conditions, water detection for leak risk, status sensors for open or closed events, and electrical or industrial inputs for machines and process signals. Then connect them through the gateway that fits the site.
Start with the question each asset needs to answer. The sensor choice becomes much easier from there.
Need help with your application?
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