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DSE Model 7560MK1 Main Control and ATS Operators Manual
057-015 7560MK1 OPERATING MANUAL ISSUE 10 10/02/09 AM
57
TYPICAL BUILDING MANAGEMENT SCHEME USING RS485 MONITORING
CAUTION! -. RS485 cabling must be 120
Ω
Ω
Ω
Ω
impedance cable, specified for use with
RS485. 120
Ω
Ω
Ω
Ω
terminating resistors must be fitted to the first and last devices on the bus.
Some PC RS485 cards are already fitted with this resistor, and in this case should not be
fitted externally. If in doubt, consult the supplier of your PC RS485 card.
If the 7510MK1 controller is the ‘last’ device on the bus, then it’s RS485 connection must be
suitably terminated with a 120
Ω
Ω
Ω
Ω
resistor as detailed in the specification laid out in the RS485
standard.
Recommended cable BELDEN 9841 120
Ω
Ω
Ω
Ω
RS485 cable.
DSE part number 016-030.
NOTE: - The RS485 output uses ‘MODBUS’ protocol. It is possible to use third party
software to monitor and control the 7560MK1 module via this protocol.
Please refer to Deep Sea Electronics Plc for details.
9.2.5 MODBUS
The RS485 output uses Modbus communications protocol. This uses a master-slave technique to
communicate. Only the Master can initiate a packet transaction, called a ‘query’. When appropriate
the slave (7560MK1 Module) responds to the query and provides the information requested by the
master.
All supported data can be read and written as specified in the register table (documentation is
available from Deep Sea Electronics Plc.).
When the 7560MK1 Module receives a query it will respond by either supplying the requested
register data or performing the requested action. A slave device (the 7560MK1 module) will never
initiate communications on the Modbus™ link. The 7560MK1 can only be configured as a slave
device. The Master can only query individual slaves. Refer to the Modbus™ protocol document for
more details.
Refer to the Link7000plus Manual for further details on communications expansion.
NOTE:- 7560MK1 controller only available with RS485 communications.