DEEP SEA ELECTRONICS PLC - Home Mega Global Solution

DSE 5xxx Configuration Software Manual7.3 RS485 LINK TO CONTROLLERThe RS485 enabled 52xx/53xx modules are able to communicate with a PC or other RS485enabled device over a standard RS485 connection. Typical uses of RS485 are :Direct connection to a remote PC running the 5xxx series configuration software. RS485 iscapable of communication over a distance of 1.2km where suitable 120RS485 cable isinstalled.Connection to a building management to allow mains, generator and engine parameters/alarmconditions to be displayed along with information from other devices (air conditioning, firealarm system etc).Typical connections ofRS485 PC system(master) to RS485 52xxcontroller (slave)NOTE:- The RS485 system will comprise of one MODBUS master (typically a PC)and up to 31 MODBUS slaves. The 52xx/53xx modules are always MODBUS slavedevices. To ensure correct operation a suitable 120 terminal resistor must be fittedto each end of the RS485 connection bus.Caution!:- The A and B lines of the 485 network should be terminated at each endwith a 120resistor.Some RS485 devices (PC cards in particular) are already fitted with a terminatingresistor. However if they are not instaled as an ‘end of line’ device then suchterminating resistors must be removed. Other RS485 devices may be fitted with a‘switchable’ resistor, again this must be switched out if the device is not instaled asan ‘end of line’ device.86DSE 5xxx Configuration software ISSUE 2 02/07/04 AM