ProSoftTechnology’s HART (Highway Addressable Remote Transducer) multi-dropcommunication modules for Rockwell Automation’s ControlLogix, SLC 500,PLC5, and Schneider Electric’s Quantum processors allow networks toaccess temperature, pressure, and multivariable units. The HARTmulti-drop modules feature:
•    Multi-drop field metwork
•    Read/write data
•   Four independent HART master ports, each user-configurable with up to 100 commands and up to 15devices per port (point-to-point and multi-drop modes)
•    Can be configured as a secondary master (i.e., handheld configuration device)
•    Supports available HART commands including universal, common practice, and device-specific commands
•   Independently configurable channels for reading process-variabledata and configuration data from the instruments
•   Data read from the devices is made available to the processoracross the backplane for use in control applications
•    Burst mode for faster update of data from a single slave

With auto-polling,the HART modules automatically sense and determine devices on thechannel. The Burst communicationmode enables three to four data updates per second. In Burst mode, theslave device is configured to continuously broadcast a standard HARTreply message. The master receives the message at the higher speed andcan be configured to instruct the Slave when to stop. The HART modulesalso allow two communicating masters per channel. The primary andsecondary masters can be a PC, handheld, or DCS.