T-String is very useful in a variety of applications, however the design was driven by the demand for economical temperature measurements in electronic equipment racks and cabinets. The spacing and length are optimized for a 72" rack. It will measure temperature strata from top to bottom at 30cm intervals.
The T-String is designed to run on the 1-Wire bus, and consists of 6 temperature sensors mounted in parallel. Each one of the
DS18B20 sensors has a unique 16 digit address. One end of the cable is terminated with a male RJ45 connector. The first sensor is mounted 92cm from the RJ45 connector, with the remaining 6 sensors placed 30cm apart.
NOTE: There is a memory device (
DS2431) on the cable, approximately 6 inches from the RJ45 connector. The device looks exactly like the sensors - it is not a sensor. The
DS2431 is used to identify the position of each sensor in the string. T-String will report the sensor closest to the RJ45 connector first and then each sensor in progression out to the end of the string.
The high temperature range of the T-String is limited by the PVC coating on the cable. The rated temperature for the PVC sheathing is 60°C. The approximate response and recovery times of the
DS18B20 sensors can be seen in appendix 1 of the
T-Sense manual. The cable is 1 pair Cat5E construction, with pins 1 and 3 of the
DS18B20 sensor tied together forming the ground, or return, line. Pin 2, the data line is brought directly to the connector.
Each sensor is mounted on a small printed circuit board and enclosed by our low pressure molding process. The upper half of the
DS18B20 sensor is not molded, allowing response times that are very close to a bare sensor. The benefits of the molding process are: Very small cross sectional dimension permits minimal resistance to air flow; No conductive surfaces are exposed; Provides excellent strain relief on all connections; Highly weather resistant and, though it has not been tested, it is likely to be water proof.
Custom T-Strings can be ordered. Customer specifications can define over-all length, spacing between sensors and number of sensors up to a maximum of 15. A minimum order of 10 T-Strings is required. Price will be quoted as a "special".
