The devices of the DVM keypad controller module bus are used for simple and intuitive control of products with an RS232 interface.
The special feature of the DVM bus is the combination of powering and bus signals via a standard RJ45 network patch cable infrastructure. There is no requirement for the category of the cable – the cross-section only influences the maximum bus length.
The operating voltage of the modules is between 12 and 24V DC.
In maximum use, the bus allows 16 modules on a maximum bus length of 100 meters with a patch cable cross-section of at least AWG24.
Communication between the modules is electrically based on RS232.
The RJ45 port 1 (labeled PREV) is assigned as follows:
- Pair 1/2 accommodates the RS 232 interface PREVIOUS
- Pair 3/6 is unused
- Pair 4/5 supplies +12…+24V
- Pair 7/8 serves as reference potential (GROUND)
The RJ45 port 2 (labeled NEXT) is assigned as follows:
- Pair 1/2 accommodates the RS 232 interface NEXT (RX/TX crossed)
- Pair 3/6 is unused
- Pair 4/5 supplies +12…+24V
- Pair 7/8 serves as reference potential (GROUND)
The PREVIOUS and NEXT interfaces can be used both for RS232 communication with external devices and also for networking several modules to form a bus. The position of the module in the bus defines the function of the interfaces:
- a single module can communicate with external devices via both interfaces
- in a bus configuration, the first module can communicate with external devices via the PREVIOUS interface and the last module via the NEXT interface
The system power supply unit provides the power for a maximum of two buses and makes the PREVIOUS interface of the first bus module available on a pluggable Euroblock connector for simple connection to the device to be controlled.