Programming Guide
Marathon MM Rev. D7 Jul 2017 77
10.10 RS485 Communication
The serial RS485 communication can be either in 2-wire or 4-wire mode.
HM=2 sets the sensor into 2-wire communication mode.
HM=4 sets the sensor into 4-wire communication mode
For setting the baud rate, one of the following two commands must be selected.
D=576 sets the baud rate to 57600, baud rate must be given with 3 numbers (003, 012, 024,
096, 192, 384, 576, 115).
BR=57600 sets the baud rate to 57600, baud rate must be given with up to 6 numbers (300, 1200,
2400, 9600, 19200, 38400, 57600, 115200)
In case of using the sensor in 2-wire mode the baud rate is limited to 38400.
10.11 Multidrop Mode
Up to 32 devices can be connected within an RS485 multidrop network, see section 6.4 Multiple Sensors
in a Network, page 32. To direct a command to one sensor among the 32 possible, it is necessary to
“address” a command. Therefore, a 3-digit number is set prior the command. The 3-digit number is
determined between 001 and 032. A unit with the address 000 is a single unit and not in multidrop
mode.
XA=024 sets the device to address 24
Changing an address:
(e.g., the address is change from 17 to 24)
command answer
“017?E” “017E0.950” // asking one sensor on address 17
“017XA=024” “017XA024” // setting of a new address
“024?E” “024E0.950” // asking same sensor now on address 24
If a command is transferred, starting with the 3-digit number 000, all units (with addresses from 001 to
032) connected will get this command - without to send an answer.
command answer
“024?E” “024E0.950”
“000E=0.5” will be executed from all sensors, no answer
“024?E” “024E0.500”
“012?E” “012E0.500”
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