The Bus Controller MOD BUS Creator is designed to structuring (chopping) an entire system into small portions with an isolated local data bus in each portion. Such local sections of the data transmission bus can operate, depending on the device option, according to the RS-485 standard interface (PW-120-485 unit) or Teta interface (PW-120-T unit). Each local section of the data bus has its separate, adjustable protection means for protection against overloads and voltage surges and is provided with logic separation for data transmission lines.
In case of a physical defect of a data bus wire or a failure of any device connected to a bus section governed by MOD BUS Creator only a portion of the system is endangered to become inoperable. The control module carries out validation and filtration of data received from the data bus and cuts off power voltage if a short fault or sparking takes place.
In addition, the Field BUS port of the device offers enhanced immunity to electromagnetic interferences (in particular, voltage surges), hence systems that use that port for field communication are better protected against consequences of surged caused, for instance, by lightning effects.
Operation principle
The module continuously monitors status of Field Bus lines by measuring voltages, currents and rates, how often transmission frames with erroneous format are transmitted down data bus lines. When a threshold limit set up by a user for electric current is exceed, the unit is switch over to the operation mode of a current supply source. If the mentioned threshold is exceeded for one second or more, power voltage for the data bus is completely cut off and an error is reported to the control system. The device also performs periodical checks of the data bus resistance. Upon the overload status on the data bus spontaneously disappears, the power voltage is automatically restored with no need for an operator intervention. In spite of a short fault or sparking between data lines and power supply line, data frames are received by destination devices in a undisturbed format and construed as correct ones. The MOD BUS Creator enables data separation on the logic level, since it receives characters as data frames, verified formats of frames and resends the frames with filtration of interferences or distortions. In addition, the rate of defective frames at the side of Field BUS lines is measured. Eventually, if the permissible limit for percentage of defective frames (data packages) is exceeded, the transmission between Field BUS and Internal BUS is completely interrupted and a failure is reported. The failure status expires after the undisturbed communication is restored.