HART modem HM01 is designed to convert RS232 signals to a HART communication protocol according to the Bell 202 Standard. It operates in half-duplex mode, the ransmission direction follows the RTS signal level found on the personal computer serial interface. The modem provides easy connection between a personal computer and a device equipped with HART protocol communication. Communication is based on using additional digital transmission of information which are superimposed on the 4 to 20 mA current output of the device.
In addition to maintenance and diagnostic data it is possible to transmit through the connection data in digital form such as value corresponding to the sensor output current and other measured variables. By this way, one sensor can measure and transmit several physical variables. Easy access to maintenance and diagnostic information of connected devices enables monitoring of an actual sensor status and by means of setting program in the PC it is possible to perform simple change in sensor settings as well. Besides, monitoring of easured physical value by input sensor current is still held.
The construction of hart modem HM01 enables simple link to the connecting wiring of the sensor. There is no need to disconnect the sensor. Simultaneously it ensures galvanic separation between the measuring circuit and connected personal computer. The HM01 modem is primarily intended for maintenance purposes. In case of its permanent installation to the measuring circuit it is necessary to remove used measuring hooks and to connect the cables to the connection wiring appropriately.
Communication software for HART modem HM01
There is a wide range of communication applications for use with sensors, provided by sensor manufacturers, or by third companies. Some of them are free, some are paid. For example the most known ones are:
- PactWare from ICS GmbH (freeware)
- HartServer from Hart Communication Foundation (30 day trial version)