Single-Point Temperature String Assembly
Single-point strings are used to determine water temperature at one location, typically at the surface.
To assemble a single-point temperature string, first connect the male UW plug connector on the T-Node FR to the female UW receptacle connector on an Underwater Cable.
Figure 1: Connect T-Node FR to underwater connection cable
Then connect the supplied UW underwater plug to the female UW receptacle connector on the T-Node FR to terminate the string.
Figure 2: Connect underwater plug (also called a “bushing”) to female end of T-Node FR
Multi-Point Temperature String Assembly
Multi-point strings are used to determine temperature at various locations. Typically of interest are temperature distributions vertically in a water column or horizontally along a stream or riverbed.
During the assembly of a multi-point temperature string, the nodes must be organized by Modbus address, with the first node being placed at some known reference point (usually closest to the water’s surface for vertical strings). Each node must be programmed with a unique Modbus address and the addresses within a string must be sequential.
Note that nodes must be assembled in ascending order, with the lowest Modbus address connected to the data logger. Always check each mating connector for an o-ring before securing any underwater connection.
To add the sensors in the Sensor Properties of the iChart Setup Device Wizard, highlight the appropriate sensor in the Available Parameters list. T-Node FR strings typically begin with Temp 00 as the first node. Click Add to add the number of T-Node FR devices that are included in the string. Enter the correct Modbus address of the first node under Modbus Settings. iChart software automatically assigns the addresses of the remaining sensors.
If the sensors are to be connected to Port P1 or T on an SDL500, click Show Detail. Under Switch Power, select SW.A (12V,200mA). Enter 10 in the Duration (sec) box.
Figure 3: Modbus Sensor Properties, adding the sensor in iChart’s Setup Device Wizard
Click OK to finish.
To begin assembling a multi-point string, first gather all T-Node FRs and Underwater Cables. Set the components out on a clean table or lab bench.
Select a single underwater cable as the first component in the temperature string, and connect it to the UW plug end of the T-node FR with the lowest Modbus address. Sensors will be assigned Modbus addresses based on serial numbers from the factory, so the lowest serial number will have the lowest Modbus address.
Continue the assembly with another underwater cable. Attach the plug end of the second cable to the receptacle end of the first T-Node FR in the string.
Proceed with additional T-Node FR sensor attachments, each followed by an underwater cable. Be sure to keep track of variations in underwater cable lengths if non-uniform spacing is desired. Also make sure to terminate the string with the supplied UW underwater plug.
When attaching the T-Node FR string to a mooring line, take special care to leave slack in the connecting underwater connection cables.
REV: 13H06