This User Guide focuses on the Solinst Model 301 Water Level Temperature Sensor (WLTS) for use as a sensor in a 4-20mA set up. Configuration, communication, installation and specifications are included.
4-20mA (4 to 20 MilliAmp) is a point-to-point or multi-drop circuit mainly used in the process automation field to transmit signals from devices and sensors in the field to a controller. It sends an analog signal from 4 to 20 mA that represents 0 to 100% of some process variable. In the case of the WLTS, the variables are water level (pressure) and temperature.
1.1 WLTS 4-20mA Interface Overview
The WLTS Current Loop Adaptor reads temperature and pressure values from a connected WLTS, converting to two channels of 4-20mA current outputs.
To connect the WLTS to the user supplied equipment, you must ensure correct wire-to-wire connection, including a continuous external power supply to the WLTS Current Loop Adaptor. Power supplied must be between 8.5V and 36V DC. The WLTS connects to a Communication Cable (vented or non) which connects to the WLTS Current Loop Adaptor. The WLTS Current Loop Adaptor is then connected to the user supplied equipment.
A simple PC Software Utility is used to configure the WLTS. The WLTS must be set with an Address of 1, Baud Rate of 19,200, Even Parity and 1 Stop bit. The Software Utility is also used to perform diagnostics on the WLTS and the WLTS Current Loop Adaptor.
