Dip Switch Settings; Rs-485 Node Address; Rs-485 Communication Settings - Procon A1M Installation Manual

3. DIP switch settings

There is a bank of 8 DIP switches on the MelcoBEMS MINI (A1M) labeled 'CONFIGURATION'. These switches are
used to configure communication settings and to enable some features.

3.1. RS-485 Node address

When BACnet MS/TP protocol has been selected (see section 3.3) the node address is used as the Station ID.
When Modbus RTU protocol has been selected (see section 3.3) The node address is used as the Slave ID.
Any node address in the range 1 – 30 can be chosen using switches 1 – 5. The address is set in binary, where the
switch positions have the following values:
To get the node address, add together the value for each switch set ON. For example, to set address 13, set switches
1, 3 and 4 ON (1 + 4 + 8 = address 13).
When all switches 1 – 5 are set to the ON position the node address is set in software by writing to a Modbus register
(see Modbus Holding Registers section).
Note: When all switches are set to the OFF position a node address of 1 is assumed.
Note: Each MelcoBEMS MINI (A1M) connected on the same RS-485 network must be set to a unique node address.

3.2. RS-485 communication settings

The RS-485 settings are set using DIP switch 6.
When the switch is in the OFF position the Baud Rate and Parity settings are set in software by writing to Modbus
registers (see Modbus Holding Register section).
The number of data bits is fixed at 8 and the number of stop bits is fixed at 1.
Switch number
1
2
3
4
5
Switch 6 RS-485 communication settings
OFF Baud Rate and Parity set in software
ON
Value when switch is set to ON
1
2
4
8
16
9600 baud, no parity
10