HART® (Highway Addressable Remote Transducer) is a communication protocol based upon the Bell 202 telephone communication standard and uses the FSK (frequency shift keying) principle. The signal consists of two parts, the analogue 4-20 mA current loop and a superimposed digital variable frequency signal.
Traditionally the 4-20 mA loop is used for control and the superimposed digital signal for feedback and configuration. The CVA utilises the signals in this way. Setup and operation for the 4-20 mA signal is the same as for the standard 4-20 mA control. Configuration and feedback using the HART® digital signal can be achieved using the host connected to the CVA to select the parameters required.
The majority of the CVA user configurable settings can be made over the HART® communication protocol. In addition to this the following HART® parameters can also be adjusted:
- HART® Tag
- Device ID
- Date Code
See HART® Literature page for further details