ST61 is a tutorial kit for Foundation Fieldbus (FF) transmitter developers. It is intended for instrument vendors with devices that support Modbus RTU. It comprises a PC program, providing the human interface and a transmitter circuit board (T610). The communication between the T610 and the target instrument is based on Modbus. The FF module will operate as a Master for the internal communication.
ST61 is a tool suited for learning the FF protocol and to provide guidance for an instrument vendor that shall specify FF functionality in own products.
The Starter kit comes with the National Instruments (NI) configurator for a laptop PC. It also contains a USB card and the Device Description, DD, for the T610. The software will instruct the user how to access parameters in the device from the Function-, Resource- and the Transducer block.
The Transducer block contains the dynamic variables and the set-up parameters for connecting a link to a Modbus instrument. Parameters such as data rate, parity and address of the dynamic variable, can be configured.
The T610 is a round transmitter board with a diameter of 65 mm. It is loop-powered and the power draw from the bus is 20 mA. The Modbus physical communication can either be UART CMOS, RS232 or RS485 signals. .
The T610 contains a galvanic isolation, isolating the Modbus instrument from the FF bus. A few circuits on the instrument side of the galvanic isolation are powered from the instrument. This allows the instrument itself to be separately powered, whereas the T610 is powered from the bus.
The NI configurator is used for set-up, test and fault detection. It runs the DD and allows all parameters defined in the DD to be observed and altered. The configurator allows:
- Instrument configuration
- Network parameter configuration
- Control loop design, including routing of traffic and timing definitions.
- Down loading of schedules to all connected devices.
- Operating in the control loop as a LAS (Link Active Scheduler)