T-Node FR Temperature Sensor

The NexSens T-Node FR Temperature Sensor provides high precision measurements in a connectorized and addressable architecture for water quality profiling.

Features

Titanium Thermistor

Each node features an integral titanium thermistor secured and epoxied in a protective housing for underwater deployments.

Marine-Grade Cable

Nodes are connected in-series using marine-grade cables with braided Kevlar core and double O-ring seals. Cables are available in increments from 0.5m to 50m.

High Accuracy

Each sensor is accurate to +/-0.075 C. The exposed titanium thermistor makes direct contact with water, allowing readings to stabilize within 60 seconds.

Data Output

Temperature data is transmitted on a RS-485 Modbus RTU string bus for integration with data loggers and SCADA systems.

Expandable

Optional accessories include water quality sensors, pressure sensors, signal splitters, cable clamps, mooring line, and communication adapters.

Documents

Tech Specs

Sensor: Thermistor
Range: 0 to 45 C (32 to 113 F)
Accuracy: +/-0.075 C
Resolution: 0.01 C
T90 Response Time: 60 seconds
Refresh Rate: 2 seconds
Maximum Sensors: 250
Maximum Length: 1219m (4000 ft.)
Maximum Depth: 200m (656 ft.)
Communications: RS-485 Modbus RTU
Power Requirement: 4-28 VDC
Current Draw Per Node: 1.3mA active; 0.35mA sleep; 0.05mA deep sleep
Connection Seal: Double o-ring, gland and face seal
Connector: 8 pin, sensorBUS
Dimensions: 13.46cm L x 3.56cm Dia. (5.3" L x 1.4" Dia.)

Q&A

What is RS-485 Modbus RTU?

RS-485 Modbus RTU is a digital communications protocol in which the sensor outputs data. Standardizing how the data is sent from the sensor makes the integration into a data logger or PLC much more straightforward. RS-485 Modbus RTU is an addressable protocol that offers significantly more sensor capacity than other protocols such as SDI-12. This allows the T-Node FR and TS210 temperature strings to accommodate up to 250 sensors along a maximum of 4000 feet of cable. Most data loggers and programmable logic controllers (PLCs) support Modbus.

For what applications is the T-Node FR optimized?

The T-Node FR is used in a variety of applications from water storage tanks to temperature profiling in lakes and reservoirs. In lakes and reservoirs, temperature strings help identify stratification and lake turnover. They are also used in selective withdrawal dams to determine the optimal location to withdraw water. A single temperature node can be used for basic water or ambient air temperature monitoring.

What are common sensors to add onto a T-Node FR string?

Dissolved oxygen sensors are frequently added to thermistor strings to help identify hypoxic zones in lakes. A two-way sensor splitter can replace any temperature node in the string and allow for integration of a third party sensor that outputs data over SDI-12 or RS-485 Modbus RTU.

Accessories

NexSens UW Extension Cables

NexSens UW Sensor Port Plug

NexSens 3/16" Stainless Steel Mooring Lines

NexSens UW Receptacle to Flying Lead Cables

NexSens RS-485 UW Sensor USB Adapters

NexSens Thermistor String Mooring Clamp Kit

NexSens RS-485 to RS-232 Adapter

Case Studies

Washington Reservoir Temperature Changes

There are many major rivers flowing through the Pacific Northwest. Like others around the country, they are outfitted with various dams and reservoirs that are used to control their movements, provide energy and maintain drinking water supplies for those living around them. The U.S. Army Corps of Engineers (USACE) plays a big hand in managing and maintaining the structures that corral these rivers. Of significance for engineers with the USACE’s […]

Eastern Lake Erie Dynamics

Lake Erie’s western basin has received a lot of attention in recent years, as it has hosted large and toxic algal blooms that seem to come every summer. But there are still plenty of valuable environmental data to be gleaned from studying in the lake’s deeper and less algae-prone eastern basin. Researchers at Buffalo State University know the value of monitoring in this basin firsthand, as they have maintained a […]

Jordan Pond Clarity Tracking

Jordan Pond is one of the most transparent lakes in Maine, but the water body has seen cloudier waters in recent years. Declines in clarity began back in the 1990s and the drops appeared to accelerate, with monitoring by the National Park Service charting a 2-meter drop in Secchi disk readings there from 1999 to 2014. Several hypotheses were put forth for the lake’s loss in clarity. Scientists suspected that […]