RS232 SIDE:
» speed 115 200 Baud » connection length 10 m » connector D-SUB 9 » power supply 9V 100 mA DC
RS485 SIDE:
» speed 57 600 Baud » connection length 1 km » connector Terminal Blok » isolation 2,5 kV RMS
» temperatures 0°C .. +70°C » dimensions 108x43x28 mm » weight 60g

Mm-I485/bibi

Isolated RS232-RS485 interface for the bibi system

General device characteristics

The isolated interface MM-I485 allows many devices with the RS485 interface to be connected to one RS232 port in a computer.
The bibi system uses a specially configured interface - described as MM-I485/bibi - which allows effective cooperation with bibi system controllers. Apart from the standard function (changing RS232 transmissions into RS485 transmissions) it acts as a Master responsible for proper addressing of controllers in a RS485 network.
You can connect up to 100 bibi-K12 controllers to one interface.

Interface power supply

The MM-I485 set includes a power supplier used to supply the interface. Power is supplied at the RS232 side of the device.

The RS232 connection to PC

This link is a D-SUB9 socket. It can be plugged directly into the COM port of a computer or by using a typical screened RS232 DB-9 DB-9 cable.
The MM-I485 interface uses 4 signal wires: RxD, TxD, RTC, CTS and the GND ground wire.

Isolation

Devices in an RS485 network can be installed in different, remote parts of a building. That is why the ground potential of each controller can be different. If a lightning strucks near the building or there is an overvoltage the difference of potentials can reach very big values.
To avoid the flow of too big currents which appear during such situations, the interface is equipped with galvanic isolation which withstands 2,5 kV RMS.
In addition all other RS485 devices from the bibi system have the same galvanic isolation.

The RS485 connection

The RS485 connection must have the form of a single line (cannot branch) which runs through all connected controllers and the MM-I485 interface. The maximum length of such a connection is 1000 m. It is possible to connect individual devices by short offshoots from the main line. Maximum length of such an offshoot is 10 m. A connection with short offshoots makes it easier to disconnect (if necessary) one of the controllers without braking connection with others.

The connections should be made using a UTP cable (commonly used in computer networks). The connection uses two pairs of wires.

A detailed description of the controller along with a connection diagram can be found in the data sheet.