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Serial Communications

  /  Serial Communications

Serial communications allows for a much greater bandwidth and more information transfer capability than traditional 4 – 20 mA signaling. Ontrac produces a wide range of serial communication options through the use of an optional communications board. These can be used with both Multitrac and Easytrac actuators.

These include:


Ontrac offers Profibus DP (Decentralised Peripherals) up to a baud rate of 1.5Mbit/s. Our actuators are supplied with active bus termination. The electrical connections are via RS485 type A.


Ontrac offers Modbus RTU protocol communications at a baud rate up to 38.4kbits/s. Our factory default speed is 9.6kbits/s giving a 1.5km maximum distance between nodes. We use a master / slave query response polling cycle with CRC (Cyclic Redundancy Check).


Ontrac can provide HART Communication Protocol (Highway Addressable Remote Transducer) connectivity. HART allows use of conventional 4 – 20 mA wiring