Macurco Modbus RS-485 User Instructions page 9

Changing MRS-485 settings
The DIP switches are to set the Modbus address and are also used to change the MRS-485 settings. Valid Modbus addresses are
between 1 and 247 where switch 1 is the least significant bit (LSB) and switch 8 is the most significant bit (MSB). Address 254 is
used to place the MRS-485 in programming mode and the rest of addresses (248 to 253, 255, 0) are invalid MODBUS addresses.
Programming Mode
When the address is set to 254 the MRS-485 enters programming mode and the LED pattern: Alternating RED/GREEN every 200
milliseconds, indicates that the MRS-485 is ready and waiting for the user to enter new settings using the 8 switches. Using the 8
switches the user can change the communication settings like baud rate and parity as well as the registration behaviour.
When looking at the switches with the "Address" marking on top, the switches are defined from left to right as:
- Switch 8, switch 7 and switch 6 are used to modify baud rate
- Switch 5 and switch 4 are used to modify parity
- Switch 3 and switch 2 are used to modify registration mode
- Switch 1 is used to request to save the new settings
Switch 8 Switch 7
OFF OFF
OFF OFF
OFF ON
OFF ON
ON OFF
ON OFF
ON ON
ON ON
Switch 5 Switch 4
OFF OFF
OFF ON
ON OFF
ON ON
Registration mode can be latched or unlatched. MRS-485 is always using data from a valid registration but when registration is
latched it will also compare the saved value with the new one and set a flag if it is different. This way, by reading the flag, you can
check if it is a different sensor type and you always get data about the sensor present.
Switch 3 Switch 2
OFF OFF
OFF ON
ON OFF
ON ON
Switch 6 Description
OFF Default baud rate (19200 Bd)
ON 4800 Bd
OFF 9600 Bd
ON 19200 Bd (Default value)
OFF 38400 Bd
ON 57600 Bd
OFF 115200 Bd
ON Do not change
Description
Default parity (EVEN)
Parity is ODD
Parity is NONE
Do not change
Description
Default registration mode (Registration not latched)
Registration not latched (Default value)
Registration is latched
Do not change
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