Environmental monitoring systems provide an affordable and reliable way to track critical conditions such as temperature, humidity and flow levels that are important to maintain smooth operations across many industries. These monitoring systems provide real-time alerts when readings fall outside of pre-set parameters, allowing personnel to quickly address issues before they become costly problems. At the center of every effective monitoring system are the environmental monitoring sensors that collect and transmit the data needed to make informed decisions.
Any Sensaphone device can serve as a complete environmental monitoring system when paired with the proper environmental monitoring sensors. This cloud-based monitoring platform can remotely monitor up to 12 sensor inputs, supporting both analog and digital sensors. By selecting the right sensors for a specific environment and application, organizations can improve system performance, reduce maintenance costs, minimize downtime, and better protect equipment, products, and facilities.With so many environmental monitoring sensors on the market, determining the best combination for your application can be challenging. This guide explores the different types of environmental monitoring sensors compatible with Sensaphone Sentinel devices, how they work, and what you should consider during installation to build a reliable and effective monitoring system.
Types of Environmental Monitoring Sensors Compatible with Sensaphone Systems
Most Sensaphone environmental monitoring systems support four primary types of environmental monitoring sensors. Understanding how each sensor works will help you select the best solution for your application.
2.8K Thermistors
A thermistor is a temperature-sensing device whose electrical resistance changes with temperature. The Sensaphone device measures the resistance and converts it into a temperature reading.
2.8K thermistors are designed for lower temperature applications, with sensing ranges from -121 °F to 115 °F (-85 °C to 46 °C). Sensaphone offers several 2.8K thermistor environmental monitoring sensors capable of measuring temperatures as low as -112 °F (-80 °C). This makes them ideal for freezers, cold storage facilities, and other low-temperature environments.
Before selecting a thermistor, ensure that the Sensaphone device supports the full temperature range required of your application. Some monitoring devices may not be able to display the entire range supported by the sensor
10K Thermistors
10K thermistors operate on the same principle as 2.8K thermistors but are designed for higher temperature ranges. Sensaphone's 10K thermistor sensors typically measure temperature ranges from 35 °F to 140 °F (2 °C to 60 °C).
As with any temperature sensor, verify compatibility with your Sensaphone device before purchase to ensure accurate readings throughout the desired temperature range.
Dry Contact Sensors
Dry contact sensors work as are either open or closed. When the state of the switch changes, the Sensaphone device detects the change and triggers an alarm notification.
While dry contact sensors do not provide numerical measurements, they are effective for detecting conditions that require immediate attention. Examples include a medical freezer door left open, a water leak, equipment failure and a high-water condition detected by a float switch.
Examples of dry contact sensors include:
- Motion detectors
- Power failure sensors
- Equipment failure sensors
- Humidity or temperature switches
- Door open/unauthorized access
- Water detectors
Multiple dry contact sensors can be connected together to create a single monitoring zone. All Sensaphone monitoring devices support dry contact sensors.
4-20mA Sensors
These types sensors, technically known as transducers, provide the most detailed information to your Sensaphone device. They operate by transmitting a signal ranging from 4mA to 20mA. The Sensaphone device interprets this signal and converts it into a corresponding measurement value.
For example, a humidity sensor with a range of 0 to 100% Relative Humidity (RH) may be configured so that:
• 4mA = 0% RH
• 20mA = 100% RH
Any signal between 4 mA and 20 mA is translated proportionally into the appropriate reading.
Unlike thermistors and dry contact sensors, 4-20 mA sensors require an external power supply. We recommend using our power supply with battery backup to ensure continuous operation. In the event of a power outage, this battery backup will keep the sensor powered and communicating with your Sensaphone device.
Since 4-20 mA is an industry-standard signal, a wide variety of specialized sensors are available from manufacturers to support numerous monitoring applications
Examples of 4-20mA sensors include:
Installing Environmental Monitoring Sensors
Installing sensors into your remote monitoring system is typically a straightforward process that most users can complete without technical support. Most sensors connect using two wires that terminate directly at the Sentinel’s terminal block. Simply insert the wires into the appropriate terminals and tighten the connections using a screwdriver. Thermistor and dry contact sensors are not polarity-sensitive, so either wire can be connected to either terminal.
Installing 4-20 mA sensors is slightly more complex because you need to wire in an external power supply. Be sure to follow the wiring instructions provided with the sensor and power supply to ensure proper operation.
Sensors can be installed at a distance from the Sensaphone device by extending the sensor cable. For most indoor applications, standard unshielded cables work well. However, for cables that run longer than 250 feet or for outdoor installations, shielded cable is recommended. Connecting the shield to earth ground helps minimize electrical interference and maintain signal accuracy.
Before installation, consult the owner's manual to verify the recommended wire gauge for your specific sensor type and cable distance.
Programming Sensors
Once the sensors are installed, the final step is configuring your Sensaphone system to recognize and monitor them. For auto-dialer monitoring systems, sensor programming is typically performed locally using the device keyboard. For cloud-based monitoring systems such as Sentinel, programming can be completed from any internet-connected computer, tablet, or smartphone through the system’s web interface.
If you have any questions about installation or programming, we offer free technical support Monday through Friday, 8 A.M. to 5 P.M. EST.
Selecting the right Sensaphone devices and environmental monitoring sensors is key to designing an effective environmental monitoring system. Our knowledgeable support team can help you choose the best combination of equipment your specific application and monitoring requirements.
