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  • Non-Isolated Control Master Board

    Control Master uses a Master–Slave principle of operation. In all systems there is one “Master Controller” board which is connected to a computer via a standard USB lead and up to 30 slave boards. The job of the Master is to allow the PC to send and receive data to any of the slave boards. The Master Controller has an "on-board" RS485 driver which provides the necessary signal conditioning to allow communications with slave boards up to a massive 1Km (0.62 Miles) away from the controller. The Master also has an on-board Microcontroller which is dedicated to performing two main functions..

    1. Handling the USB interface to the PC
         2. Handling the RS485 serial communications to the slave boards.

    There are two different types of Master Controller available. The “Non-isolated Master” is the simplest form offering a direct connection between the PC the Master and the Slave boards. In this configuration all of the boards share the same ground connection as the PC. In the majority of applications this is perfectly acceptable. For info on the fully isolated version click here


    One of the few differences between the Isolated Master and the Non-Isolated version is the power supply requirements. The Non-Isolated master becomes fully operational as soon as you connect it to a USB port. i.e. it receives all of its power from the USB port.

    The Master simply connects to a slave by connecting two wires. These wires are connected to terminals TL1 and are labelled A and B. Connect the A on the Master to the A on the slave and similarly B to B. This wire can be up to 1Km long and should be twisted wherever possible. The signalling which takes place over this pair of wires is standard RS485 signals which are differential in nature. This means that they are highly immune to electrical noise coming from the surroundings where the cable is routed. Twisting the wires together improves this immunity by making it less likely that an external electrical signal will cause any differential interference voltage in the wires. Connecting to more than one slave is simply a continuation of the two wire connection. This can either be a separate two wires starting at the master and going, perhaps in a different direction, to the second slave or it can be a connection from slave one to slave two. In either case always ensure you connect terminals A to A and B to B. The flexibility in forming a continuous “chain” of slaves connected together and to the Master or to connect them directly to the Master in a “star” configuration allows your wiring to reflect the most suitable routing for your own application.
    Also, remember that each slave can also be connected to other slaves in a star configuration. The only limitation is that no slave can be any more than 1Km from the Master in terms of total length of shortest cable route. This flexibility makes the distributed control system very suitable to a wide variety of installations

    In particularly noisy (electrically) environments, such as heavy industrial applications, it may be advisable to use additional shielding for the pair of wires. In this case you can purchase commonly available screened twisted pair cable which has the two wires plus an overall metal foil screen, which is in turn covered in a plastic outer layer. When using this type of cable the two wires should be connected as normal and the metal foil screen should be connected to the terminal marked “SCN” on the Master and on each slave.


    (Note: This is not a "kit of parts" , it is fully assembled and tested)

    Compatible with Windows XP, Vista, 7, 8 and 10
        To download a copy of the user manual for this board, right click on the link on the right and choose "save target as". This will allow you to download a PDF copy of the manual

        You will need Adobe Reader installed on your PC to read this document. Adobe reader is available for free download from Adobe using the link to the right..

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